An improved hybrid Navier-Stokes/full potential method for computation of unsteady compressible flows

Author(s):  
O Mello ◽  
L Sankar
Author(s):  
Yan Jin

Abstract The turbulent flow in a compressor cascade is calculated by using a new simulation method, i.e., parameter extension simulation (PES). It is defined as the calculation of a turbulent flow with the help of a reference solution. A special large-eddy simulation (LES) method is developed to calculate the reference solution for PES. Then, the reference solution is extended to approximate the exact solution for the Navier-Stokes equations. The Richardson extrapolation is used to estimate the model error. The compressor cascade is made of NACA0065-009 airfoils. The Reynolds number 3.82 × 105 and the attack angles −2° to 7° are accounted for in the study. The effects of the end-walls, attack angle, and tripping bands on the flow are analyzed. The PES results are compared with the experimental data as well as the LES results using the Smagorinsky, k-equation and WALE subgrid models. The numerical results show that the PES requires a lower mesh resolution than the other LES methods. The details of the flow field including the laminar-turbulence transition can be directly captured from the PES results without introducing any additional model. These characteristics make the PES a potential method for simulating flows in turbomachinery with high Reynolds numbers.


Author(s):  
Vladislav Balashov ◽  
Evgenii Savenkov ◽  
Alexander Zlotnik

Abstract We propose a numerical algorithm for simulations of two-component viscous compressible isothermal flows with surface effects in 3D domains of complex shape with voxel representation of geometry. The basic mathematical model is the regularized system of Navier–Stokes–Cahn–Hilliard equations. Simulations of droplet spreading over a flat base and displacement of one liquid by another one in a pore space of real rock sample are carried out. The simulation results demonstrate the applicability and good efficiency of the used system of equations, the corresponding difference scheme, and its implementation algorithms for numerical solution of the considered class of problems.


1997 ◽  
Author(s):  
Mert Berkman ◽  
Lakshmi Sankar ◽  
Charles Berezin ◽  
Michael Torok ◽  
Mert Berkman ◽  
...  

Author(s):  
M. S. Anand ◽  
R. Eggels ◽  
M. Staufer ◽  
M. Zedda ◽  
J. Zhu

A general-purpose combustion Computational Fluid Dynamics (CFD) design analysis tool has been developed. The method is pressure-based and applicable to both incompressible and compressible flows. The unstructured finite-volume approach used can take arbitrary shapes of mesh cells to resolve complicated geometries. Turbulence is simulated either by Reynolds-Averaged Navier-Stokes (RANS) or by Large Eddy Simulation (LES) approaches. Combustion is modeled by various combinations of combustion chemistry and combustion-turbulence models including transport probability density function (PDF) model. A Lagrangian approach is used to simulate fuel spray droplet. The resulting tool has being used in routine combustor simulations for a variety of commercial and military combustor development programs. Application examples presented include simulations of several combustors and comparisons with available rig data.


2013 ◽  
Vol 477-478 ◽  
pp. 281-284
Author(s):  
Jie Yang ◽  
Song Ping Wu

An immersed boundary method based on the ghost-cell approach is presented in this paper. The compressible Navier-Stokes equations are discretized using a flux-splitting method for inviscid fluxes and second-order central-difference for the viscous components. High-order accuracy is achieved by using weighted essentially non-oscillatory (WENO) and Runge-Kutta schemes. Boundary conditions are reconstructed by a serial of linear interpolation and inverse distance weighting interpolation of flow variables in fluid domain. Two classic flow problems (flow over a circular cylinder, and a NACA 0012 airfoil) are simulated using the present immersed boundary method, and the predictions show good agreement with previous computational results.


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