Mark Glauser - Academia.edu (original) (raw)
Papers by Mark Glauser
Bulletin of the American Physical Society, Nov 20, 2005
With the aim of implementing closed-loop control on the flow exiting an axisymmetric jet nozzle, ... more With the aim of implementing closed-loop control on the flow exiting an axisymmetric jet nozzle, and to be able to capture the dynamics of the flow as it evolves downstream of the jet exit, we are developing dynamical systems based on the Navier-Stokes equations. The evolution equation is guided by a Galerkin projection of the Navier-Stokes equations onto the Proper Orthogonal Decomposition (POD) eigenfunctions. The coefficients of the ordinary differential equations for each streamwise position are then solved for using experimental data of the flow based on the moments method initially developed by the Poitiers group. A time-prediction of the evolution of the flow can then be retrieved from given initial conditions. The main experimental limitation lies in acquiring time-resolved data of the flow which is needed in the resolution of the dynamical system. The progress in the effort of training the dynamical system with time-resolved data of the jet and its implementation for control will be discussed.
APS Division of Fluid Dynamics Meeting Abstracts, Nov 1, 2003
The cross correlation between fluctuating lip pressure and the instantaneous stream-wise velocity... more The cross correlation between fluctuating lip pressure and the instantaneous stream-wise velocity of a 2-inch diameter, cold (104oF), high Mach number, axisymmetric, jet with a maximum co-flow of 5velocity measurements are acquired using a Dantec Dynamic LDA/PDA system with a Stabilite 2017 argon ion laser head, capable of capturing all three components (u,v,w) of the velocity field. Pressure fluctuations at
Bulletin of the American Physical Society, Nov 21, 2017
Submitted for the DFD17 Meeting of The American Physical Society Toward the Experimental Characte... more Submitted for the DFD17 Meeting of The American Physical Society Toward the Experimental Characterization of an Unmanned Air System Flow Field JOHN-MICHAEL VELARDE, JACOB CONNORS, MARK GLAUSER, Syracuse Univ-The velocity flow field around a small unmanned air system (sUAS) is investigated in a series of experiments at Syracuse University. Experiments are conducted in the 2'x2' sub-sonic wind tunnel at Syracuse University and the Indoor Flow Lab. The goal of these experiments is to gain a better understanding of the rich, turbulent flow field that a sUAS creates. Comparison to large, multi-rotor manned vehicles is done to gain a better understanding of the flow physics that could be occurring with the sUAS. Regions of investigation include the downwash, above the vehicle, and far downstream. Characterization of the flow is performed using hotwire anemometry. Investigation of several locations around the sUAS show that dominant frequencies exist within the flow field. Analysis of the flow field using power spectral density will be presented as well as looking at which parameters have an effect on these dominant frequencies.
This report is published in the interest of scientific and technical information exchange and its... more This report is published in the interest of scientific and technical information exchange and its publication does not constitute the Government's approval or disapproval of its ideas or findings.
Public reporting burden for this collection of information is estimated to average I hour per res... more Public reporting burden for this collection of information is estimated to average I hour per response, including the time for reviewing instructions, searching data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden to Washington Headquarters Service, Directorate for Information Operations and Reports,
Bulletin of the American Physical Society, Nov 20, 2005
Bulletin of the American Physical Society, Nov 20, 2005
Submitted for the DFD05 Meeting of The American Physical Society Multiwindow PIV measurements aro... more Submitted for the DFD05 Meeting of The American Physical Society Multiwindow PIV measurements around a breathing manikin DAVID MARR, RITESH SHETH, MARK GLAUSER, HIROSHI HIGUCHI , Syracuse University-The presented work includes multiscale measurements via a stereo article Image Velocimetry (PIV) system to view a pair of twocomponent windows of dissimilar scale using a varied focal length. These measurements are taken in the breathing zone of an isothermal breathing manikin (from mouth) in an environmental chamber of average office cubicle dimensions without ventilation and are analogous to an oscillatory jet. From these phaseaveraged measurements, we can extract information concerning length scales, turbulence quantities and low dimensional information in order to both determine correlation between data at different length scales as well as continuing research in exposure assessment for the indoor environment. In this talk we will present these turbulence quantities and interpret their influence on the breathing zone. While the largest scale is that of the room itself, we find that the relevant spatial scales associated with the breathing zone are much lower in magnitude. In future experiments, we will expand the multi window PIV technique to include PIV window configured to obtain scales of order the cubicle simultaneously with those of the breathing zone. This will aid in our understanding of the combined impact of these multiple scales on occupant exposure in the indoor environment.
Bulletin of the American Physical Society, Nov 20, 2006
Submitted for the DFD06 Meeting of The American Physical Society Identification and Control of No... more Submitted for the DFD06 Meeting of The American Physical Society Identification and Control of Noise Source Mechanisms in a Transonic Axisymmetric Jet ANDRE HALL, JEREMY PINIER, MARK GLAUSER, Syracuse University-An experimental examination aimed at characterizing the aeroacoustic effect linked to the turbulent mixing of the exhausted jet plume with the ambient air in high-speed jets is comprised of a 50.8mm nozzle at Mach 0.85, operated under both heated (260oC) and room temperature (0oC) conditions. Both the hydrodynamic near-field and acoustic far-field pressure regions are examined. The near-field using an azimuthal array of fifteen (15) dynamic response pressure transducers positioned near the jets lip, and the far-field using a boom array of six (6) acoustic microphones (6.35mm in diameter). Instantaneous 3 component velocity measurements are acquired, simultaneously, in the r, theta plane at several streamwise positions between z/D=3:8 (the region where the sound producing events are found to be dominant) using a stereo PIV system. This data set is utilized in conjunction with multi-point low-dimensional techniques to characterize a low-dimensional description of the velocity field, with minimal effect on far-field acoustics. The low-dimensional description of the velocity field is examined to identify the dominant noise source mechanism in both jets. Calculation of a modified Lighthill source term, and azimuthal modal forcing, are used as a measure of source intensity and a gauge for noise reduction schemes, respectively. Where control of noise sources is concerned, a modal analysis of the near-field region has shown that modal forcing may prove a promising method. We greatly acknowledge the support of the AFOSR and the CNY-PR AGEP Alliance.
Bulletin of the American Physical Society, Nov 19, 2007
Submitted for the DFD07 Meeting of The American Physical Society Exposure assessment involving en... more Submitted for the DFD07 Meeting of The American Physical Society Exposure assessment involving entrainment during human motion in the indoor environment DAVID MARR, IAN SPITZER, MARK GLAUSER, Syracuse University-Recent experimental studies have shown the effects of motion on the human thermal plume (Settles). When utilizing low speed ventilation designs, this natural convection is a primary driving force of the flow. Interference with this flow reduces the effectiveness of a displacement design and therein reduces air quality and comfort levels in the indoor environment. Human motion has been found to increase mixing in a room (Mora and Gadgil) with displacement ventilation, a negative effect due to the nature of the design. This investigation is the culmination of PDA and PIV measurements around a thermal manikin and the direct impact seated human rotation has on air velocity, particle concentration and size associated with the thermal plume. This common indoor motion in a cubicle setting may assist in exposure studies and ventilation design to determine the effectiveness of displacement style ventilation in a near realistic setting.
Bulletin of the American Physical Society, Nov 19, 2012
Submitted for the DFD12 Meeting of The American Physical Society Characterization of an Actively ... more Submitted for the DFD12 Meeting of The American Physical Society Characterization of an Actively Controlled Three-Dimensional Turret Wake PATRICK SHEA, MARK GLAUSER, Syracuse University-Three-dimensional turrets are commonly used for housing optical systems on airborne platforms. As bluff bodies, these geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study looked to use dynamic suction in both open and closed-loop control configurations to actively control the turret wake. The flow field was characterized using dynamic pressure and stereoscopic PIV measurements in the wake of the turret. Results showed that the suction system was able to manipulate the wake region of the turret and could alter not only the spatial structure of the wake, but also the temporal behavior of the wake flow field. Closed-loop, feedback control techniques were used to determine a more optimal control input for the flow control. Similar control effects were seen for both the steady open-loop control case and the closed-loop feedback control configuration with a 45% reduction in the suction levels when comparing the closed-loop to the open-loop case. These results provide unique information regarding the development of the baseline three-dimensional wake and the wake with three different active flow control configurations.
Bulletin of the American Physical Society, Nov 24, 2013
on airborne platforms. These geometries generate highly turbulent wakes that decrease the perform... more on airborne platforms. These geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study used dynamic suction in both open and closed-loop control configurations to actively control the wake turret. The experiments were carried out at a Reynolds number of 5x10 5 , and the flow field was characterized using stereoscopic PIV measurements acquired in the wake of the turret. These data were processed using traditional single-point statistics which showed that the active control system was able to significantly alter the wake of the turret. Using multi-point correlations, turbulent characteristics such as the integral length scale can be calculated. For the turret wake, estimates of the integral length scales were found to be highly dependent upon the region of the flow that was evaluated, especially when comparing the shear layers to the center of the wake. With the application of the active control, the integral length scales were generally found to increase.
Bulletin of the American Physical Society, Nov 21, 2010
Bulletin of the American Physical Society, Nov 20, 2005
Submitted for the DFD05 Meeting of The American Physical Society Prediction capabilities in a tur... more Submitted for the DFD05 Meeting of The American Physical Society Prediction capabilities in a turbulent flow field JULIE AUSSEUR, JEREMY PINIER, MARK GLAUSER, HIROSHI HIGUCHI, Syracuse University-Part of our continuous efforts to implement an optimal closed-loop feedback control of the flow over a NACA 4412 airfoil is the development of an accurate model of the flow state. Combining several low-dimensional techniques, such as the Proper Orthogonal Decomposition (POD) and the modified Linear Stochastic Measurement (mLSM), we are able to access real-time information on the flow state just by sensing the pressure on the surface of the airfoil. In previous studies (Glauser et al. 2004), we have demonstrated using a simple proportional feedback control that the first POD coefficient estimated through the mLSM procedure alone contains this valuable information. In 2001 Ukeiley et al. derived a dynamical system able to predict the temporal dynamics of the POD modes and therefore of the flow. This presentation will mainly focus on the different methods that we are applying to solve this low-dimensional set of ODEs. We will present and discuss our prediction results as well as their incorporation in a more elaborate control system.
Bulletin of the American Physical Society, Nov 19, 2006
speed jet, measurements of the near field pressure around the periphery of a Mach 0.85 jet are co... more speed jet, measurements of the near field pressure around the periphery of a Mach 0.85 jet are combined with simultaneous measurements of the far-field acoustic pressure to quantify the azimuthal nature of the acoustic pressure sources in jet. Results indicate that the near field pressure is low dimensional and dominated by both azimuthal modes 0 and 1. Only azimuthal mode 0, however, is well correlated with the acoustic far field suggesting that, from a time-averaged perspective, the most efficient near field pressure source is axisymmetric. Using a streamwise microphone array in conjunction with azimuthal filtering, the streamwise evolution of the axisymmetric pressure source is examined, including the convection speed and streamwise growth and decay of the sources in the jet.
51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, Jan 5, 2013
An experimental investigation was performed on a three-dimensional, non-conformal turret with the... more An experimental investigation was performed on a three-dimensional, non-conformal turret with the goal of gaining a more detailed understanding of the spatial and temporal nature of the turret wake. The turret flow field was investigated using particle image velocimetry and dynamic surface pressure measurements, both with and without active flow control. Active flow control for the current work was applied at the leading edge of the turret aperture using steady suction and was matched to a configuration used for control of aero-optic distortions. The results of these experiments give insight into the complex, three-dimensional wake that develops as a result of the turret geometry as well as the significant changes that can be achieved with the application of active flow control, even when applied only to the aperture region of the cap geometry.
Springer eBooks, Jan 7, 2008
Part of our continuous efforts to implement an effective closed-loop feedback control of the flow... more Part of our continuous efforts to implement an effective closed-loop feedback control of the flow over a NACA 4412 airfoil is the obtention of an accurate estimate of the actual flow state. An elaborate controller combines both prediction and measurement techniques to obtain a precise estimation of the control variable. In this paper we focus on the measurement process. We first present the different candidates for the control variable, and describe the low-dimensional techniques employed. We then focus on the estimation methods that will be incorporated in the controller in order to access the state variable from the pressure real-time measurements. The investigation of the dynamics in the flow field and the correlations between the variables at stake reveal the benefits brought by a spectral estimation approach.
Experimental Thermal and Fluid Science, May 1, 1998
Abstract This paper presents results of LDV measurements in a complex three-dimensional (3D) turb... more Abstract This paper presents results of LDV measurements in a complex three-dimensional (3D) turbulent flow. The experimental configuration studied, shown in Fig. 1 , provides a complex 1 parameter (step height) three-dimensional flow with two-dimensional (2D) relaxation limits in the spanwise direction (that is, 2D channel flow and 2D backstep). Note that this flow is more complex than the simple 2D back-step described by Eaton and Johnston, 1981 , AIAA Journal, vol. 19, pp. 1093–1100. However, when spanwise limits are taken out from either side of the centerline the flow relaxes to two well studied 2D flows. On the block side, the spanwise limit results in a 2D turbulent channel flow. On the step side, the spanwise limit results in the 2D back-step flow. In the center region of the facility, however the flow is strongly 3D. The data presented here, was taken with a three component laser Velocimetry system, thus all three velocity components can be measured simultaneously. The results presented here clearly indicate that this flow provides a complex 3D flow for turbulence model calibration with the added attraction of the 2D spanwise limits. In the region within two stepheights either side in span of the streamwise step edge, secondary flows are observed. In addition, a spanwise evolving streamwise reattachment length is seen. The prediction of the secondary motions along with the spanwise evolving streamwise reattachment length found here will provide a challenging test for any turbulence model.
The public reporting burden for this collection of information is estimated to average 1 hour per... more The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Bulletin of the American Physical Society, Nov 20, 2005
With the aim of implementing closed-loop control on the flow exiting an axisymmetric jet nozzle, ... more With the aim of implementing closed-loop control on the flow exiting an axisymmetric jet nozzle, and to be able to capture the dynamics of the flow as it evolves downstream of the jet exit, we are developing dynamical systems based on the Navier-Stokes equations. The evolution equation is guided by a Galerkin projection of the Navier-Stokes equations onto the Proper Orthogonal Decomposition (POD) eigenfunctions. The coefficients of the ordinary differential equations for each streamwise position are then solved for using experimental data of the flow based on the moments method initially developed by the Poitiers group. A time-prediction of the evolution of the flow can then be retrieved from given initial conditions. The main experimental limitation lies in acquiring time-resolved data of the flow which is needed in the resolution of the dynamical system. The progress in the effort of training the dynamical system with time-resolved data of the jet and its implementation for control will be discussed.
APS Division of Fluid Dynamics Meeting Abstracts, Nov 1, 2003
The cross correlation between fluctuating lip pressure and the instantaneous stream-wise velocity... more The cross correlation between fluctuating lip pressure and the instantaneous stream-wise velocity of a 2-inch diameter, cold (104oF), high Mach number, axisymmetric, jet with a maximum co-flow of 5velocity measurements are acquired using a Dantec Dynamic LDA/PDA system with a Stabilite 2017 argon ion laser head, capable of capturing all three components (u,v,w) of the velocity field. Pressure fluctuations at
Bulletin of the American Physical Society, Nov 21, 2017
Submitted for the DFD17 Meeting of The American Physical Society Toward the Experimental Characte... more Submitted for the DFD17 Meeting of The American Physical Society Toward the Experimental Characterization of an Unmanned Air System Flow Field JOHN-MICHAEL VELARDE, JACOB CONNORS, MARK GLAUSER, Syracuse Univ-The velocity flow field around a small unmanned air system (sUAS) is investigated in a series of experiments at Syracuse University. Experiments are conducted in the 2'x2' sub-sonic wind tunnel at Syracuse University and the Indoor Flow Lab. The goal of these experiments is to gain a better understanding of the rich, turbulent flow field that a sUAS creates. Comparison to large, multi-rotor manned vehicles is done to gain a better understanding of the flow physics that could be occurring with the sUAS. Regions of investigation include the downwash, above the vehicle, and far downstream. Characterization of the flow is performed using hotwire anemometry. Investigation of several locations around the sUAS show that dominant frequencies exist within the flow field. Analysis of the flow field using power spectral density will be presented as well as looking at which parameters have an effect on these dominant frequencies.
This report is published in the interest of scientific and technical information exchange and its... more This report is published in the interest of scientific and technical information exchange and its publication does not constitute the Government's approval or disapproval of its ideas or findings.
Public reporting burden for this collection of information is estimated to average I hour per res... more Public reporting burden for this collection of information is estimated to average I hour per response, including the time for reviewing instructions, searching data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden to Washington Headquarters Service, Directorate for Information Operations and Reports,
Bulletin of the American Physical Society, Nov 20, 2005
Bulletin of the American Physical Society, Nov 20, 2005
Submitted for the DFD05 Meeting of The American Physical Society Multiwindow PIV measurements aro... more Submitted for the DFD05 Meeting of The American Physical Society Multiwindow PIV measurements around a breathing manikin DAVID MARR, RITESH SHETH, MARK GLAUSER, HIROSHI HIGUCHI , Syracuse University-The presented work includes multiscale measurements via a stereo article Image Velocimetry (PIV) system to view a pair of twocomponent windows of dissimilar scale using a varied focal length. These measurements are taken in the breathing zone of an isothermal breathing manikin (from mouth) in an environmental chamber of average office cubicle dimensions without ventilation and are analogous to an oscillatory jet. From these phaseaveraged measurements, we can extract information concerning length scales, turbulence quantities and low dimensional information in order to both determine correlation between data at different length scales as well as continuing research in exposure assessment for the indoor environment. In this talk we will present these turbulence quantities and interpret their influence on the breathing zone. While the largest scale is that of the room itself, we find that the relevant spatial scales associated with the breathing zone are much lower in magnitude. In future experiments, we will expand the multi window PIV technique to include PIV window configured to obtain scales of order the cubicle simultaneously with those of the breathing zone. This will aid in our understanding of the combined impact of these multiple scales on occupant exposure in the indoor environment.
Bulletin of the American Physical Society, Nov 20, 2006
Submitted for the DFD06 Meeting of The American Physical Society Identification and Control of No... more Submitted for the DFD06 Meeting of The American Physical Society Identification and Control of Noise Source Mechanisms in a Transonic Axisymmetric Jet ANDRE HALL, JEREMY PINIER, MARK GLAUSER, Syracuse University-An experimental examination aimed at characterizing the aeroacoustic effect linked to the turbulent mixing of the exhausted jet plume with the ambient air in high-speed jets is comprised of a 50.8mm nozzle at Mach 0.85, operated under both heated (260oC) and room temperature (0oC) conditions. Both the hydrodynamic near-field and acoustic far-field pressure regions are examined. The near-field using an azimuthal array of fifteen (15) dynamic response pressure transducers positioned near the jets lip, and the far-field using a boom array of six (6) acoustic microphones (6.35mm in diameter). Instantaneous 3 component velocity measurements are acquired, simultaneously, in the r, theta plane at several streamwise positions between z/D=3:8 (the region where the sound producing events are found to be dominant) using a stereo PIV system. This data set is utilized in conjunction with multi-point low-dimensional techniques to characterize a low-dimensional description of the velocity field, with minimal effect on far-field acoustics. The low-dimensional description of the velocity field is examined to identify the dominant noise source mechanism in both jets. Calculation of a modified Lighthill source term, and azimuthal modal forcing, are used as a measure of source intensity and a gauge for noise reduction schemes, respectively. Where control of noise sources is concerned, a modal analysis of the near-field region has shown that modal forcing may prove a promising method. We greatly acknowledge the support of the AFOSR and the CNY-PR AGEP Alliance.
Bulletin of the American Physical Society, Nov 19, 2007
Submitted for the DFD07 Meeting of The American Physical Society Exposure assessment involving en... more Submitted for the DFD07 Meeting of The American Physical Society Exposure assessment involving entrainment during human motion in the indoor environment DAVID MARR, IAN SPITZER, MARK GLAUSER, Syracuse University-Recent experimental studies have shown the effects of motion on the human thermal plume (Settles). When utilizing low speed ventilation designs, this natural convection is a primary driving force of the flow. Interference with this flow reduces the effectiveness of a displacement design and therein reduces air quality and comfort levels in the indoor environment. Human motion has been found to increase mixing in a room (Mora and Gadgil) with displacement ventilation, a negative effect due to the nature of the design. This investigation is the culmination of PDA and PIV measurements around a thermal manikin and the direct impact seated human rotation has on air velocity, particle concentration and size associated with the thermal plume. This common indoor motion in a cubicle setting may assist in exposure studies and ventilation design to determine the effectiveness of displacement style ventilation in a near realistic setting.
Bulletin of the American Physical Society, Nov 19, 2012
Submitted for the DFD12 Meeting of The American Physical Society Characterization of an Actively ... more Submitted for the DFD12 Meeting of The American Physical Society Characterization of an Actively Controlled Three-Dimensional Turret Wake PATRICK SHEA, MARK GLAUSER, Syracuse University-Three-dimensional turrets are commonly used for housing optical systems on airborne platforms. As bluff bodies, these geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study looked to use dynamic suction in both open and closed-loop control configurations to actively control the turret wake. The flow field was characterized using dynamic pressure and stereoscopic PIV measurements in the wake of the turret. Results showed that the suction system was able to manipulate the wake region of the turret and could alter not only the spatial structure of the wake, but also the temporal behavior of the wake flow field. Closed-loop, feedback control techniques were used to determine a more optimal control input for the flow control. Similar control effects were seen for both the steady open-loop control case and the closed-loop feedback control configuration with a 45% reduction in the suction levels when comparing the closed-loop to the open-loop case. These results provide unique information regarding the development of the baseline three-dimensional wake and the wake with three different active flow control configurations.
Bulletin of the American Physical Society, Nov 24, 2013
on airborne platforms. These geometries generate highly turbulent wakes that decrease the perform... more on airborne platforms. These geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study used dynamic suction in both open and closed-loop control configurations to actively control the wake turret. The experiments were carried out at a Reynolds number of 5x10 5 , and the flow field was characterized using stereoscopic PIV measurements acquired in the wake of the turret. These data were processed using traditional single-point statistics which showed that the active control system was able to significantly alter the wake of the turret. Using multi-point correlations, turbulent characteristics such as the integral length scale can be calculated. For the turret wake, estimates of the integral length scales were found to be highly dependent upon the region of the flow that was evaluated, especially when comparing the shear layers to the center of the wake. With the application of the active control, the integral length scales were generally found to increase.
Bulletin of the American Physical Society, Nov 21, 2010
Bulletin of the American Physical Society, Nov 20, 2005
Submitted for the DFD05 Meeting of The American Physical Society Prediction capabilities in a tur... more Submitted for the DFD05 Meeting of The American Physical Society Prediction capabilities in a turbulent flow field JULIE AUSSEUR, JEREMY PINIER, MARK GLAUSER, HIROSHI HIGUCHI, Syracuse University-Part of our continuous efforts to implement an optimal closed-loop feedback control of the flow over a NACA 4412 airfoil is the development of an accurate model of the flow state. Combining several low-dimensional techniques, such as the Proper Orthogonal Decomposition (POD) and the modified Linear Stochastic Measurement (mLSM), we are able to access real-time information on the flow state just by sensing the pressure on the surface of the airfoil. In previous studies (Glauser et al. 2004), we have demonstrated using a simple proportional feedback control that the first POD coefficient estimated through the mLSM procedure alone contains this valuable information. In 2001 Ukeiley et al. derived a dynamical system able to predict the temporal dynamics of the POD modes and therefore of the flow. This presentation will mainly focus on the different methods that we are applying to solve this low-dimensional set of ODEs. We will present and discuss our prediction results as well as their incorporation in a more elaborate control system.
Bulletin of the American Physical Society, Nov 19, 2006
speed jet, measurements of the near field pressure around the periphery of a Mach 0.85 jet are co... more speed jet, measurements of the near field pressure around the periphery of a Mach 0.85 jet are combined with simultaneous measurements of the far-field acoustic pressure to quantify the azimuthal nature of the acoustic pressure sources in jet. Results indicate that the near field pressure is low dimensional and dominated by both azimuthal modes 0 and 1. Only azimuthal mode 0, however, is well correlated with the acoustic far field suggesting that, from a time-averaged perspective, the most efficient near field pressure source is axisymmetric. Using a streamwise microphone array in conjunction with azimuthal filtering, the streamwise evolution of the axisymmetric pressure source is examined, including the convection speed and streamwise growth and decay of the sources in the jet.
51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, Jan 5, 2013
An experimental investigation was performed on a three-dimensional, non-conformal turret with the... more An experimental investigation was performed on a three-dimensional, non-conformal turret with the goal of gaining a more detailed understanding of the spatial and temporal nature of the turret wake. The turret flow field was investigated using particle image velocimetry and dynamic surface pressure measurements, both with and without active flow control. Active flow control for the current work was applied at the leading edge of the turret aperture using steady suction and was matched to a configuration used for control of aero-optic distortions. The results of these experiments give insight into the complex, three-dimensional wake that develops as a result of the turret geometry as well as the significant changes that can be achieved with the application of active flow control, even when applied only to the aperture region of the cap geometry.
Springer eBooks, Jan 7, 2008
Part of our continuous efforts to implement an effective closed-loop feedback control of the flow... more Part of our continuous efforts to implement an effective closed-loop feedback control of the flow over a NACA 4412 airfoil is the obtention of an accurate estimate of the actual flow state. An elaborate controller combines both prediction and measurement techniques to obtain a precise estimation of the control variable. In this paper we focus on the measurement process. We first present the different candidates for the control variable, and describe the low-dimensional techniques employed. We then focus on the estimation methods that will be incorporated in the controller in order to access the state variable from the pressure real-time measurements. The investigation of the dynamics in the flow field and the correlations between the variables at stake reveal the benefits brought by a spectral estimation approach.
Experimental Thermal and Fluid Science, May 1, 1998
Abstract This paper presents results of LDV measurements in a complex three-dimensional (3D) turb... more Abstract This paper presents results of LDV measurements in a complex three-dimensional (3D) turbulent flow. The experimental configuration studied, shown in Fig. 1 , provides a complex 1 parameter (step height) three-dimensional flow with two-dimensional (2D) relaxation limits in the spanwise direction (that is, 2D channel flow and 2D backstep). Note that this flow is more complex than the simple 2D back-step described by Eaton and Johnston, 1981 , AIAA Journal, vol. 19, pp. 1093–1100. However, when spanwise limits are taken out from either side of the centerline the flow relaxes to two well studied 2D flows. On the block side, the spanwise limit results in a 2D turbulent channel flow. On the step side, the spanwise limit results in the 2D back-step flow. In the center region of the facility, however the flow is strongly 3D. The data presented here, was taken with a three component laser Velocimetry system, thus all three velocity components can be measured simultaneously. The results presented here clearly indicate that this flow provides a complex 3D flow for turbulence model calibration with the added attraction of the 2D spanwise limits. In the region within two stepheights either side in span of the streamwise step edge, secondary flows are observed. In addition, a spanwise evolving streamwise reattachment length is seen. The prediction of the secondary motions along with the spanwise evolving streamwise reattachment length found here will provide a challenging test for any turbulence model.
The public reporting burden for this collection of information is estimated to average 1 hour per... more The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.