Immersed boundary conditions in global, flux-driven, gyrokinetic simulations

A spectral method for solving the steady flow of a shear-thinning Ellis fluid is discussed for the case of a planar channel with corrugated boundaries. Polynomial approximations are employed for the velocity and viscosity distributions in the regions around singularities. The proposed algorithm employs a fixed computational domain with the physical domain of interest submerged inside the computational domain. The flow boundary conditions are imposed using the concept of immersed boundary conditions. The method, thus, eliminates the need for grid generation. The algorithm relies on Fourier expansions in the flow direction and Chebyshev expansions in the transverse direction. Various tests confirm spectral accuracy of the algorithm.

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Use of Immersed Boundary Method for the Analysis of Electro-Osmotic Flow Generated by a Pair of Cylindrical Electrodes in a Micro-Cavity

ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer, Parts A and B ◽

10.1115/mnht2008-52206 ◽

2008 ◽

Author(s):

Dolfred V. Fernandes ◽

Sangmo Kang ◽

Yong K. Suh

Keyword(s):

Boundary Conditions ◽

Stokes Equations ◽

Ionic Concentration ◽

Ion Concentration ◽

Dimensional Case ◽

Immersed Boundary ◽

Bench Mark ◽

Step Method ◽

Fractional Step Method ◽

Micro Cavity

The bulk motion of an aqueous solution induced by the application of DC electric field is studied numerically. The physical model consists of a micro-cavity with two completely polarizable cylindrical electrodes. The electric double layer (EDL) model coupled with Navier-Stokes equations governing the electroosmotic flow has been described. The Nernst-Planck model uses two extra equations for the prediction of ion concentration. We employed IB (immersed boundary) technique for the implementation of boundary conditions and semi-implicit fractional-step method for solving the governing equations. A new method is described for implementing concentration boundary conditions on the electrodes. The bench mark problems, driven cavity flow and flow over a cylnder were used for the validation of our present code. The numerical results are compared with the analytical results obtained using Gouy-Chapman-Stern model for the one dimensional case. For the two dimensional case the flow field and the ionic concentration distributions obtained shows that the electoosmotic effect is predominant in the thin region around the electrode.

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Large Eddy Simulation of a jet flow with a suction/ejection system using immersed boundary conditions

Journal of Wind Engineering and Industrial Aerodynamics ◽

10.1016/j.jweia.2010.06.003 ◽

2010 ◽

Vol 98 (10-11) ◽

pp. 618-627 ◽

Cited By ~ 2

Author(s):

M. Salinas-Vázquez ◽

W. Vicente ◽

C. González-Rodríguez ◽

E. Barrios-Bonilla ◽

A. Espinosa-Gayosso

Keyword(s):

Large Eddy Simulation ◽

Boundary Conditions ◽

Jet Flow ◽

Immersed Boundary ◽

Eddy Simulation ◽

Large Eddy

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A Sharp-Interface Immersed Boundary Method for Simulating High-Speed Compressible Inviscid Flows

10.21203/rs.3.rs-47580/v2 ◽

2020 ◽

Author(s):

Junjie Wang ◽

Xiangyu Gu ◽

Jie Wu

Keyword(s):

Boundary Conditions ◽

Immersed Boundary Method ◽

High Speed ◽

Compressible Flows ◽

Wall Slip ◽

Sharp Interface ◽

Immersed Boundary ◽

Boundary Method ◽

Lift Off ◽

Inviscid Compressible Flows

Abstract This paper presents a robust sharp-interface immersed boundary method for simulating inviscid compressible flows over stationary and moving bodies. The flow field is governed by Euler equations, which are solved by using the open source library OpenFOAM. Discontinuities such as those introduced by shock waves are captured by using Kurganov and Tadmor divergence scheme. Wall-slip boundary conditions are enforced at the boundary of body through reconstructing flow variables at some ghost points. Their values are obtained indirectly by interpolating from their mirror points. A bilinear interpolation is employed to determine the variables at the mirror points from boundary conditions and flow conditions around the boundary. To validate the efficiency and accuracy of this method for simulation of high-speed inviscid compressible flows, four cases have been simulated as follows: supersonic flow over a 15 angle wedge, transonic flow past a stationary airfoil, a piston moving with supersonic velocity in a shock tube and a rigid circular cylinder lift-off from a flat surface triggered by a shock wave. Compared to the exact analytical solutions or the results in literature, good agreement can be achieved.

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Numerical modeling of chemical interaction between a fluid and rocks

Numerical Methods and Programming (Vychislitel'nye Metody i Programmirovanie) ◽

10.26089/nummet.v20r440 ◽

2019 ◽

pp. 457-470

Author(s):

К.А. Гадыльшина ◽

Т.С. Хачкова ◽

В.В. Лисица

Keyword(s):

Numerical Modeling ◽

Fluid Flow ◽

Boundary Conditions ◽

Chemical Interaction ◽

Pore Space ◽

Immersed Boundary ◽

Finite Difference Schemes ◽

Rock Interaction ◽

Convection Diffusion ◽

Level Set Function

Предложен алгоритм численного моделирования процессов химического взаимодействия флюида с породой в масштабе пор. Алгоритм основан на методе расщепления задачи по физическим процессам. Предполагается, что скорость течения флюида мала, а установление потока происходит мгновенно при малых изменениях геометрии порового пространства. Таким образом, поток флюида в поровом пространстве моделируется при помощи уравнения Стокса для стационарного течения жидкости. Перенос химически активного компонента описывается уравнением конвекциидиффузии с граничными условиями третьего рода. Граница порового пространства изменяется со временем и задается неявно функцией уровня. Для численного решения уравнения Стокса и уравнения конвекциидиффузии применяется метод конечных разностей с аппроксимацией краевого условия взаимодействия жидкой и твердой фазы на погруженной границе. A new algorithm for the numerical modeling of chemical fluid-rock interaction at the pore scale is proposed. The algorithm is based on splitting the problem into physical processes. It is assumed that the fluid rate is low and the fluid flow is stabilized almost instantly in the case of small changes in the pore space geometry. In the pore space, thus, the fluid flow is modeled using the Stokes equation for steady flows. The chemical reactant transport is described by the convection-diffusion equation with Robin boundary conditions at the fluid-rock interface. The pore space boundary changes with time and is implicitly given by a level-set function. We use finite-difference schemes with immersed boundary conditions to solve the Stokes and convection-diffusion equations.

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