M. Anyoji - Academia.edu (original) (raw)

Papers by M. Anyoji

A new type of wind tunnel that can simulate airfoil flow in the Mars atmosphere has been designed... more A new type of wind tunnel that can simulate airfoil flow in the Mars atmosphere has been designed and constructed at Tohoku University. This wind tunnel is driven by ejector and designed to simulate low-density Martian atmosphere consisting of CO2. The preliminary performance tests were conducted using air to investigate the operating envelop of the tunnel. It was demonstrated that this wind tunnel could cover the Reynolds number range from 10 4 to 10 5 and the Mach number range up to 0.71, allowing us to simulate low Reynolds number and high subsonic flow on Mars airplanes. Calibration tests were also conducted to investigate the flow characteristics in the test section. It was confirmed that the flow was kept uniform in the test section even when the total pressure was 1 kPa. There were significant effects of the boundary layer development on static pressure gradient along the test section. It was found that these effects of boundary layers could be corrected by inclining both the...

Proceedings of the Eighth International Conference on Engineering Computational Technology, 2000

A numerical study of the effects of airfoil shape on low Reynolds number aerodynamics is presente... more A numerical study of the effects of airfoil shape on low Reynolds number aerodynamics is presented. The large-eddy simulations are performed with 6 th-order compact finite difference scheme and 10 th-order low pass filter, and 2 nd-order backward implicit time integration with inner iterations. Systematic numerical excesses show the feasibility of the current simulations to predict flow fields around fixed-wing configurations involving a laminar separation and laminar-to-turbulence transition at low Reynolds number. At the Reynolds number of 2.3×10 4 , two types of thin and asymmetric airfoils as a target airfoil shape of micro-size air vehicle are considered. The results show that the airfoil cross section affects the formation of a laminar separation bubble and the transition to turbulence in the three-dimensional flow around the wings at low angle of attack and hence significant influence on the aerodynamic performance.

Journal of Aircraft, 2014

43rd Fluid Dynamics Conference, 2013

Journal of Visualization, 2014

A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University th... more A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University that can produce a high subsonic flow at low pressures for aerodynamic measurements of low-Reynoldsnumber aircraft wings aimed at developing aircraft applicable to the atmosphere on the planet Mars. Accurate surface pressure measurements on the wing are essential for analysis of not only aerodynamic performance, including lift and drag, but also the flow fields around the wing. This paper presents a surface pressure measurement technique using pressure-sensitive paint (PSP) applicable for Mars wind tunnel tests under low-pressure conditions. The results show that a PSP composed of palladium tetra(pentafluorophenyl) porphyrin (PdTFPP) and poly[1-(trimethylsilyl)-propyne] [poly(TMSP)] exhibits a high-pressure sensitivity at pressures as low as 1 kPa, and the absolute values of the static pressures measured by the PSP accorded well with the values derived from static pressure sensors used as a reference. A calibration methodology for the non-uniform pressure sensitivity on the test model, including a temperature calibration, is also established. The PSP technique clearly demonstrated pressure sensitivity over a distinctive low-pressure region inside a leading edge separation bubble on a flat plate at low Reynolds numbers.

Shock Waves, 2009

ABSTRACT The fragmentation of solid plates impacted by a high-speed projectile has been studied i... more ABSTRACT The fragmentation of solid plates impacted by a high-speed projectile has been studied intensively in the past. However, the ejection and shattering process of fragmented particles have not been well resolved yet. To simulate the earlier stage of particle ejection, we performed an analogue experiment of the ejection of aluminum spheres attached on a thin aluminum plate in a row and impinged at tis reverse side by a high-spee plastic cylinder of 51 mm in diameter. The ejection of spheres was observed by using a high-speed digital camera and also holographic interefrometry. These image analysis revealed the motion of ejected spheres.

Shock Waves, 2009

ABSTRACT We have developed a computer-aided analysis tool for shadowgraph and schlieren optical s... more ABSTRACT We have developed a computer-aided analysis tool for shadowgraph and schlieren optical setups with a graphical user interface by handling both the optical setups and the computational fluid dynamics. It has been demonstrated that our simulation can display simple shadowgraph and schlieren images for two-dimensional flows. In this paper, the technique is further used to analyze the detailed effects of slits and cutoffs used in a typical schlieren optical setup for axisymmetric flows. The present study successfully reveals the influences of the two factors on the schlieren image of the supersonic flow over a sphere.

50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2014

Journal of Fluid Science and Technology, 2014

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2014

Physics of Fluids, 2015

ABSTRACT Mechanisms behind the pressure distribution and skin friction within a laminar separatio... more ABSTRACT Mechanisms behind the pressure distribution and skin friction within a laminar separation bubble (LSB) are investigated by large-eddy simulations around a 5% thickness blunt flat plate at the chord length based Reynolds number 5.0 × 103, 6.1 × 103, 1.1 × 104, and 2.0 × 104. The characteristics inside the LSB change with the Reynolds number; a steady laminar separation bubble (LSB_S) at the Reynolds number 5.0 × 103 and 6.1 × 103, and a steady-fluctuating laminar separation bubble (LSB_SF) at the Reynolds number 1.1 × 104, and 2.0 × 104. Different characteristics of pressure and skin friction distributions are observed by increasing the Reynolds number, such that a gradual monotonous pressure recovery in the LSB_S and a plateau pressure distribution followed by a rapid pressure recovery region in the LSB_SF. The reasons behind the different characteristics of pressure distributions at different Reynolds numbers are discussed by deriving the Reynolds averaged pressure gradient equation. It is confirmed that the viscous stress distributions near the surface play an important role in determining the formation of different pressure distributions. Depending on the Reynolds numbers, the viscous stress distributions near the surface are affected by the development of a separated laminar shear layer or the Reynolds shear stress. In addition, we show that the same analyses can be applied to the flows around a NACA0012 airfoil.

52nd Aerospace Sciences Meeting, 2014

52nd Aerospace Sciences Meeting, 2014

A new type of wind tunnel that can simulate airfoil flow in the Mars atmosphere has been designed... more A new type of wind tunnel that can simulate airfoil flow in the Mars atmosphere has been designed and constructed at Tohoku University. This wind tunnel is driven by ejector and designed to simulate low-density Martian atmosphere consisting of CO2. The preliminary performance tests were conducted using air to investigate the operating envelop of the tunnel. It was demonstrated that this wind tunnel could cover the Reynolds number range from 10 4 to 10 5 and the Mach number range up to 0.71, allowing us to simulate low Reynolds number and high subsonic flow on Mars airplanes. Calibration tests were also conducted to investigate the flow characteristics in the test section. It was confirmed that the flow was kept uniform in the test section even when the total pressure was 1 kPa. There were significant effects of the boundary layer development on static pressure gradient along the test section. It was found that these effects of boundary layers could be corrected by inclining both the...

Proceedings of the Eighth International Conference on Engineering Computational Technology, 2000

A numerical study of the effects of airfoil shape on low Reynolds number aerodynamics is presente... more A numerical study of the effects of airfoil shape on low Reynolds number aerodynamics is presented. The large-eddy simulations are performed with 6 th-order compact finite difference scheme and 10 th-order low pass filter, and 2 nd-order backward implicit time integration with inner iterations. Systematic numerical excesses show the feasibility of the current simulations to predict flow fields around fixed-wing configurations involving a laminar separation and laminar-to-turbulence transition at low Reynolds number. At the Reynolds number of 2.3×10 4 , two types of thin and asymmetric airfoils as a target airfoil shape of micro-size air vehicle are considered. The results show that the airfoil cross section affects the formation of a laminar separation bubble and the transition to turbulence in the three-dimensional flow around the wings at low angle of attack and hence significant influence on the aerodynamic performance.

Journal of Aircraft, 2014

43rd Fluid Dynamics Conference, 2013

Journal of Visualization, 2014

A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University th... more A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University that can produce a high subsonic flow at low pressures for aerodynamic measurements of low-Reynoldsnumber aircraft wings aimed at developing aircraft applicable to the atmosphere on the planet Mars. Accurate surface pressure measurements on the wing are essential for analysis of not only aerodynamic performance, including lift and drag, but also the flow fields around the wing. This paper presents a surface pressure measurement technique using pressure-sensitive paint (PSP) applicable for Mars wind tunnel tests under low-pressure conditions. The results show that a PSP composed of palladium tetra(pentafluorophenyl) porphyrin (PdTFPP) and poly[1-(trimethylsilyl)-propyne] [poly(TMSP)] exhibits a high-pressure sensitivity at pressures as low as 1 kPa, and the absolute values of the static pressures measured by the PSP accorded well with the values derived from static pressure sensors used as a reference. A calibration methodology for the non-uniform pressure sensitivity on the test model, including a temperature calibration, is also established. The PSP technique clearly demonstrated pressure sensitivity over a distinctive low-pressure region inside a leading edge separation bubble on a flat plate at low Reynolds numbers.

Shock Waves, 2009

ABSTRACT The fragmentation of solid plates impacted by a high-speed projectile has been studied i... more ABSTRACT The fragmentation of solid plates impacted by a high-speed projectile has been studied intensively in the past. However, the ejection and shattering process of fragmented particles have not been well resolved yet. To simulate the earlier stage of particle ejection, we performed an analogue experiment of the ejection of aluminum spheres attached on a thin aluminum plate in a row and impinged at tis reverse side by a high-spee plastic cylinder of 51 mm in diameter. The ejection of spheres was observed by using a high-speed digital camera and also holographic interefrometry. These image analysis revealed the motion of ejected spheres.

Shock Waves, 2009

ABSTRACT We have developed a computer-aided analysis tool for shadowgraph and schlieren optical s... more ABSTRACT We have developed a computer-aided analysis tool for shadowgraph and schlieren optical setups with a graphical user interface by handling both the optical setups and the computational fluid dynamics. It has been demonstrated that our simulation can display simple shadowgraph and schlieren images for two-dimensional flows. In this paper, the technique is further used to analyze the detailed effects of slits and cutoffs used in a typical schlieren optical setup for axisymmetric flows. The present study successfully reveals the influences of the two factors on the schlieren image of the supersonic flow over a sphere.

50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2014

Journal of Fluid Science and Technology, 2014

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 2014

Physics of Fluids, 2015

ABSTRACT Mechanisms behind the pressure distribution and skin friction within a laminar separatio... more ABSTRACT Mechanisms behind the pressure distribution and skin friction within a laminar separation bubble (LSB) are investigated by large-eddy simulations around a 5% thickness blunt flat plate at the chord length based Reynolds number 5.0 × 103, 6.1 × 103, 1.1 × 104, and 2.0 × 104. The characteristics inside the LSB change with the Reynolds number; a steady laminar separation bubble (LSB_S) at the Reynolds number 5.0 × 103 and 6.1 × 103, and a steady-fluctuating laminar separation bubble (LSB_SF) at the Reynolds number 1.1 × 104, and 2.0 × 104. Different characteristics of pressure and skin friction distributions are observed by increasing the Reynolds number, such that a gradual monotonous pressure recovery in the LSB_S and a plateau pressure distribution followed by a rapid pressure recovery region in the LSB_SF. The reasons behind the different characteristics of pressure distributions at different Reynolds numbers are discussed by deriving the Reynolds averaged pressure gradient equation. It is confirmed that the viscous stress distributions near the surface play an important role in determining the formation of different pressure distributions. Depending on the Reynolds numbers, the viscous stress distributions near the surface are affected by the development of a separated laminar shear layer or the Reynolds shear stress. In addition, we show that the same analyses can be applied to the flows around a NACA0012 airfoil.

52nd Aerospace Sciences Meeting, 2014

52nd Aerospace Sciences Meeting, 2014