The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Guoxiang Hou - One of the best experts on this subject based on the ideXlab platform.
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sharp interface immersed boundary lattice boltzmann method with reduced spurious Pressure Oscillations for moving boundaries
Physical Review E, 2013Co-Authors: Li Chen, Guoxiang HouAbstract:A sharp-interface immersed boundary lattice Boltzmann method (IBLBM) is developed to reduce spurious-Pressure Oscillations in moving boundary problems. We adopt a cut-cell-based method, i.e., the partially saturated computational cell method, because the primary cause of spurious-Pressure Oscillations is the failure to obey the geometric conservation law near the boundary in the sharp-interface IBLBM. We modify a sharp-interface IBLBM (ghost fluid method) to fit the cut-cell approach. This boundary condition can guarantee the Dirichlet and Neumann boundary conditions for velocity and Pressure. Some simulations are shown to test the validity of the method, including a circular cylinder with motions that are at rest, moving, oscillatory, and neutrally buoyant. The results illustrate that the method reduces effectively spurious Pressure and can simulate moving boundary problems, especially when Pressure field accuracy is a key concern.
Rajat Mittal - One of the best experts on this subject based on the ideXlab platform.
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a sharp interface immersed boundary method with improved mass conservation and reduced spurious Pressure Oscillations
Journal of Computational Physics, 2011Co-Authors: Jung Hee Seo, Rajat MittalAbstract:A method for reducing the spurious Pressure Oscillations observed when simulating moving boundary flow problems with sharp-interface immersed boundary methods (IBMs) is proposed. By first identifying the primary cause of these Oscillations to be the violation of the geometric conservation law near the immersed boundary, we adopt a cut-cell based approach to strictly enforce geometric conservation. In order to limit the complexity associated with the cut-cell method, the cut-cell based discretization is limited only to the Pressure Poisson and velocity correction equations in the fractional-step method and the small-cell problem tackled by introducing a virtual cell-merging technique. The method is shown to retain all the desirable properties of the original finite-difference based IBM while at the same time, reducing Pressure Oscillations for moving boundaries by roughly an order of magnitude.
Li Chen - One of the best experts on this subject based on the ideXlab platform.
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sharp interface immersed boundary lattice boltzmann method with reduced spurious Pressure Oscillations for moving boundaries
Physical Review E, 2013Co-Authors: Li Chen, Guoxiang HouAbstract:A sharp-interface immersed boundary lattice Boltzmann method (IBLBM) is developed to reduce spurious-Pressure Oscillations in moving boundary problems. We adopt a cut-cell-based method, i.e., the partially saturated computational cell method, because the primary cause of spurious-Pressure Oscillations is the failure to obey the geometric conservation law near the boundary in the sharp-interface IBLBM. We modify a sharp-interface IBLBM (ghost fluid method) to fit the cut-cell approach. This boundary condition can guarantee the Dirichlet and Neumann boundary conditions for velocity and Pressure. Some simulations are shown to test the validity of the method, including a circular cylinder with motions that are at rest, moving, oscillatory, and neutrally buoyant. The results illustrate that the method reduces effectively spurious Pressure and can simulate moving boundary problems, especially when Pressure field accuracy is a key concern.
Jung Hee Seo - One of the best experts on this subject based on the ideXlab platform.
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a sharp interface immersed boundary method with improved mass conservation and reduced spurious Pressure Oscillations
Journal of Computational Physics, 2011Co-Authors: Jung Hee Seo, Rajat MittalAbstract:A method for reducing the spurious Pressure Oscillations observed when simulating moving boundary flow problems with sharp-interface immersed boundary methods (IBMs) is proposed. By first identifying the primary cause of these Oscillations to be the violation of the geometric conservation law near the immersed boundary, we adopt a cut-cell based approach to strictly enforce geometric conservation. In order to limit the complexity associated with the cut-cell method, the cut-cell based discretization is limited only to the Pressure Poisson and velocity correction equations in the fractional-step method and the small-cell problem tackled by introducing a virtual cell-merging technique. The method is shown to retain all the desirable properties of the original finite-difference based IBM while at the same time, reducing Pressure Oscillations for moving boundaries by roughly an order of magnitude.
Mahouton Norbert Hounkonnou - One of the best experts on this subject based on the ideXlab platform.
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dynamic response of a vaporizing spray to Pressure Oscillations approximate analytical solutions
Combustion and Flame, 2018Co-Authors: Kwassi Anani, Roger Prudhomme, Mahouton Norbert HounkonnouAbstract:Abstract In this work, we study thermal conduction and convection combined effects on frequency response to Pressure Oscillations of a spray of repetitively injected drops in a combustion chamber. The theoretical model is based on Heidmann analogy of the so called “mean droplet” which is a single spherical vaporizing droplet with constant average radius, given that this droplet is continually fed at a stationary flow rate. The feeding comes from a source point placed at the mean spherical droplet center in such a way that the injection process can be assumed to be isothermal (isothermal feeding regime) or adiabatic (adiabatic feeding regime). Drawing upon the linear decomposition of the energy conservation equation, approximate analytical solutions for the perturbed temperature field inside the droplet are obtained from some derived double confluent Heun equations. Frequency response factor of the evaporating mass is then evaluated on the basis of the Rayleigh criterion by means of the linearized equations of the gas phase. Compared to the results obtained for the previous pure conduction model of the same “mean droplet”, frequency response factor curves seem to be similar with reference to each feeding regime. Moreover, due to the radial thermal convection effect introduced in the present work, a frequency response factor curve with the same characteristic times ratio may exhibit a relatively larger frequency range for the instability domain. Data are found to be correlated in terms of period of Pressure Oscillations, of vaporization characteristics times and of fuel thermodynamic coefficients. In the isothermal feeding regime in particular, due to some possible values that can be taken by a certain thermodynamic coefficient, high and non-linear frequency responses may appear in the system.
