Boris Arcen - Academia.edu (original) (raw)
Papers by Boris Arcen
Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion models
International Journal of Multiphase Flow, 2013
ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of... more ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "normalized models" and the second one "GLM models". Nevertheless, the main differences between the normalized and GLM models have not been thoroughly investigated. Is there a model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM model proposed by Arcen and Tanière [1] and the normalized model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion models. It will be shown that the normalized dispersion model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress is not physically acceptable.
International Journal of Multiphase Flow, 2008
In this paper, the results of an international collaborative test case relative to the production... more In this paper, the results of an international collaborative test case relative to the production of a Direct Numerical Simulation and Lagrangian Particle Tracking database for turbulent particle dispersion in channel flow at low Reynolds number are presented. The objective of this test case is to establish a homogeneous source of data relevant to the general problem of particle dispersion in wall-bounded turbulence. Different numerical approaches and computational codes have been used to simulate the particle-laden flow and calculations have been carried on long enough to achieve a statistically-steady condition for particle distribution. In such stationary regime, a comprehensive database including both post-processed statistics and raw data for the fluid and for the particles has been obtained. The complete datasets can be downloaded from the web at
Assessing the Effects of Near Wall Corrections of the Force Acting on Particles in Gas-Solid Channel Flows
Volume 1: Symposia, Parts A and B, 2005
International Journal of Multiphase Flow, 2008
The paper examines the use of expressions proposed by Csanady to predict the influence of the cro... more The paper examines the use of expressions proposed by Csanady to predict the influence of the crossing trajectory and continuity effects on the decorrelation time scales of the fluid along solid particle trajectories in horizontal and downward vertical channel flows. The model is evaluated using data provided by a direct numerical simulation (DNS) of the carrier phase combined with a Lagrangian simulation of discrete particle (LS). Two particle relaxation times and two values of the gravity acceleration are considered. The results show the possibility of using Csanady's expressions in a turbulent channel flow provided that the spatial and temporal correlations anisotropy is included in the model. As in isotropic homogeneous turbulence, a decrease of the decorrelation time scales is found to be more important in the directions perpendicular to the mean relative velocity.
Volume 2, Fora: Cavitation and Multiphase Flow; Fluid Measurements and Instrumentation; Microfluidics; Multiphase Flows: Work in Progress; Fluid-Particle Interactions in Turbulence, 2014
The paper deals with gas-solid turbulent flows carrying nonspherical particles. The main objectiv... more The paper deals with gas-solid turbulent flows carrying nonspherical particles. The main objective of the present paper is to compute the hydrodynamics forces on non-spherical particles as a function of the particle orientation, for different particle shapes and a large range of particle Reynolds number. Two Direct Numerical Simulations at the scale of the particle are used, i.e. a body-fitted approach and a viscous penalty approach, in the case of a uniform flow with a single ellipsoidal particle. Results are compared with several correlations from the literature and a new proposal for the drag coefficient is given. The study is then extended to the case of a lattice of non-spherical particles to mea- * Address all correspondence to this author. sure the pressure drop and to connect it with the drag coefficient.
Computers & Fluids, 2014
An accurate prediction of the translational and rotational motion of ellipsoidal particles can be... more An accurate prediction of the translational and rotational motion of ellipsoidal particles can be only given if a complete set of correlations of the drag, lift and pitching torque coefficients is known. The present study is thus devoted to the assessment of the available correlations in the literature through a comparison with numerical results of the forces acting on a particle given by a full body-fitted direct numerical simulation (DNS) in the case of a uniform flow, for three different ellipsoidal particles, and for Reynolds number ranging from 0.1 to 290. The comparison between the computed force (or hydrodynamic coefficients) and the literature correlations shows clearly that certain precautions must be taken. The mean deviation of the most accurate correlation considered in the present study from our full DNS results can be of the order of 20% for the drag coefficient. For the lift and pitching torque coefficients, the deviations can increase up to roughly 25%. This comparison shows that further works are definitively necessary to develop a complete set of correlations for ellipsoidal particles outside Stokes regime.
Study on Langevin model parameters of velocity in turbulent shear flows
Physics of Fluids, 2010
ABSTRACT This paper deals with the stochastic equation used to predict the fluctuating velocity o... more ABSTRACT This paper deals with the stochastic equation used to predict the fluctuating velocity of a fluid particle in a nonhomogeneous turbulent flow, in the frame of probability density function (PDF) approaches. It is shown that a Langevin-type equation is appropriate provided its parameters (drift and diffusion matrices) are suitably specified. By following the approach proposed in the literature for homogeneous turbulent shear flows, these parameters have been identified using data from direct numerical simulations (DNS) of both channel and pipe flows. Using statistics extracted from the computation of the channel flow, it is shown that the drift matrix of the stochastic differential equation can reasonably be assumed to be diagonal but not spherical. This behavior of the drift coefficients is confirmed by the available results for a turbulent pipe flow at low Reynolds number. Concerning the diffusion matrix, it is found that this matrix is anisotropic for low Reynolds number flows, a property which has been observed earlier for a homogeneous turbulent shear flow. The pertinence of the present estimation of the drift and diffusion tensors is assessed through different kinds of tests including the incorporation of these parameters in a purely Lagrangian, or stand-alone, PDF computation.
Nuclear Engineering and Design, 2010
In this paper, we present how DNS is being used in the context of DNB modeling. Two particular ap... more In this paper, we present how DNS is being used in the context of DNB modeling. Two particular applications are presented: wall boiling and bubble column flow. An analysis of the relevant length scales involved shows that true DNS, where all the length scales are resolved, is necessarily restricted to flow configurations where one or a few bubbles are involved. In the context of DNB modeling, DNS can thus be used to study (i) the dynamics of the growth of a few bubbles with their eventual spreading and (ii) bubble column flows to predict the void fraction field in the near wall region. To account for collective effects in bubbly flows, we show that it is necessary to develop a new approach where the large turbulence structures and large interface deformations are captured whereas the smallest scales are modeled; this is the ISS method. The DNS and ISS methods are presented and preliminary results on the use of DNS for larger scales models are presented.
Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion models
ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of... more ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "normalized models" and the second one "GLM models". Nevertheless, the main differences between the normalized and GLM models have not been thoroughly investigated. Is there a model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM model proposed by Arcen and Tanière [1] and the normalized model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion models. It will be shown that the normalized dispersion model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress is not physically acceptable.
Taking the purpose of the presentations into consideration, the program of the symposium can be d... more Taking the purpose of the presentations into consideration, the program of the symposium can be divided mainly in two parts: a first one devoted to dispersed two-phase flows and a second one lying in non spherical particles. Both of parts will be introduced by a plenary lecture. The proceedings consist of 15 papers, which underwent a regular peer-review process. These papers can be regrouped in two parts according to the topics previously cited.
Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion models
International Journal of Multiphase Flow, 2013
ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of... more ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "normalized models" and the second one "GLM models". Nevertheless, the main differences between the normalized and GLM models have not been thoroughly investigated. Is there a model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM model proposed by Arcen and Tanière [1] and the normalized model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion models. It will be shown that the normalized dispersion model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress is not physically acceptable.
International Journal of Multiphase Flow, 2008
In this paper, the results of an international collaborative test case relative to the production... more In this paper, the results of an international collaborative test case relative to the production of a Direct Numerical Simulation and Lagrangian Particle Tracking database for turbulent particle dispersion in channel flow at low Reynolds number are presented. The objective of this test case is to establish a homogeneous source of data relevant to the general problem of particle dispersion in wall-bounded turbulence. Different numerical approaches and computational codes have been used to simulate the particle-laden flow and calculations have been carried on long enough to achieve a statistically-steady condition for particle distribution. In such stationary regime, a comprehensive database including both post-processed statistics and raw data for the fluid and for the particles has been obtained. The complete datasets can be downloaded from the web at
Assessing the Effects of Near Wall Corrections of the Force Acting on Particles in Gas-Solid Channel Flows
Volume 1: Symposia, Parts A and B, 2005
International Journal of Multiphase Flow, 2008
The paper examines the use of expressions proposed by Csanady to predict the influence of the cro... more The paper examines the use of expressions proposed by Csanady to predict the influence of the crossing trajectory and continuity effects on the decorrelation time scales of the fluid along solid particle trajectories in horizontal and downward vertical channel flows. The model is evaluated using data provided by a direct numerical simulation (DNS) of the carrier phase combined with a Lagrangian simulation of discrete particle (LS). Two particle relaxation times and two values of the gravity acceleration are considered. The results show the possibility of using Csanady's expressions in a turbulent channel flow provided that the spatial and temporal correlations anisotropy is included in the model. As in isotropic homogeneous turbulence, a decrease of the decorrelation time scales is found to be more important in the directions perpendicular to the mean relative velocity.
Volume 2, Fora: Cavitation and Multiphase Flow; Fluid Measurements and Instrumentation; Microfluidics; Multiphase Flows: Work in Progress; Fluid-Particle Interactions in Turbulence, 2014
The paper deals with gas-solid turbulent flows carrying nonspherical particles. The main objectiv... more The paper deals with gas-solid turbulent flows carrying nonspherical particles. The main objective of the present paper is to compute the hydrodynamics forces on non-spherical particles as a function of the particle orientation, for different particle shapes and a large range of particle Reynolds number. Two Direct Numerical Simulations at the scale of the particle are used, i.e. a body-fitted approach and a viscous penalty approach, in the case of a uniform flow with a single ellipsoidal particle. Results are compared with several correlations from the literature and a new proposal for the drag coefficient is given. The study is then extended to the case of a lattice of non-spherical particles to mea- * Address all correspondence to this author. sure the pressure drop and to connect it with the drag coefficient.
Computers & Fluids, 2014
An accurate prediction of the translational and rotational motion of ellipsoidal particles can be... more An accurate prediction of the translational and rotational motion of ellipsoidal particles can be only given if a complete set of correlations of the drag, lift and pitching torque coefficients is known. The present study is thus devoted to the assessment of the available correlations in the literature through a comparison with numerical results of the forces acting on a particle given by a full body-fitted direct numerical simulation (DNS) in the case of a uniform flow, for three different ellipsoidal particles, and for Reynolds number ranging from 0.1 to 290. The comparison between the computed force (or hydrodynamic coefficients) and the literature correlations shows clearly that certain precautions must be taken. The mean deviation of the most accurate correlation considered in the present study from our full DNS results can be of the order of 20% for the drag coefficient. For the lift and pitching torque coefficients, the deviations can increase up to roughly 25%. This comparison shows that further works are definitively necessary to develop a complete set of correlations for ellipsoidal particles outside Stokes regime.
Study on Langevin model parameters of velocity in turbulent shear flows
Physics of Fluids, 2010
ABSTRACT This paper deals with the stochastic equation used to predict the fluctuating velocity o... more ABSTRACT This paper deals with the stochastic equation used to predict the fluctuating velocity of a fluid particle in a nonhomogeneous turbulent flow, in the frame of probability density function (PDF) approaches. It is shown that a Langevin-type equation is appropriate provided its parameters (drift and diffusion matrices) are suitably specified. By following the approach proposed in the literature for homogeneous turbulent shear flows, these parameters have been identified using data from direct numerical simulations (DNS) of both channel and pipe flows. Using statistics extracted from the computation of the channel flow, it is shown that the drift matrix of the stochastic differential equation can reasonably be assumed to be diagonal but not spherical. This behavior of the drift coefficients is confirmed by the available results for a turbulent pipe flow at low Reynolds number. Concerning the diffusion matrix, it is found that this matrix is anisotropic for low Reynolds number flows, a property which has been observed earlier for a homogeneous turbulent shear flow. The pertinence of the present estimation of the drift and diffusion tensors is assessed through different kinds of tests including the incorporation of these parameters in a purely Lagrangian, or stand-alone, PDF computation.
Nuclear Engineering and Design, 2010
In this paper, we present how DNS is being used in the context of DNB modeling. Two particular ap... more In this paper, we present how DNS is being used in the context of DNB modeling. Two particular applications are presented: wall boiling and bubble column flow. An analysis of the relevant length scales involved shows that true DNS, where all the length scales are resolved, is necessarily restricted to flow configurations where one or a few bubbles are involved. In the context of DNB modeling, DNS can thus be used to study (i) the dynamics of the growth of a few bubbles with their eventual spreading and (ii) bubble column flows to predict the void fraction field in the near wall region. To account for collective effects in bubbly flows, we show that it is necessary to develop a new approach where the large turbulence structures and large interface deformations are captured whereas the smallest scales are modeled; this is the ISS method. The DNS and ISS methods are presented and preliminary results on the use of DNS for larger scales models are presented.
Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion models
ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of... more ABSTRACT Nowadays, two families of stochastic models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "normalized models" and the second one "GLM models". Nevertheless, the main differences between the normalized and GLM models have not been thoroughly investigated. Is there a model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM model proposed by Arcen and Tanière [1] and the normalized model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion models. It will be shown that the normalized dispersion model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress is not physically acceptable.
Taking the purpose of the presentations into consideration, the program of the symposium can be d... more Taking the purpose of the presentations into consideration, the program of the symposium can be divided mainly in two parts: a first one devoted to dispersed two-phase flows and a second one lying in non spherical particles. Both of parts will be introduced by a plenary lecture. The proceedings consist of 15 papers, which underwent a regular peer-review process. These papers can be regrouped in two parts according to the topics previously cited.