scholarly journals Mesh block refinement technique for incompressible flows in complex geometries using Cartesian grids

2009 ◽  
Author(s):  
C. Georgantopoulou ◽  
G. Georgantopoulos ◽  
S. Tsangaris
Keyword(s):  
Incompressible Flows ◽  
Complex Geometries ◽  
Cartesian Grids

Prediction of Three-Dimensional Steady Incompressible Flows Using Body-Fitted Coordinates

1993 ◽  
Vol 115 (3) ◽  
pp. 457-462 ◽  
Author(s):  
P. Tamamidis ◽  
D. N. Assanis
Keyword(s):  
Cross Section ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Computational Time ◽  
Complex Geometries ◽  
Curved Duct ◽  
Sensitivity Studies ◽  
Simplec Algorithm ◽  
Volume Method ◽  
Strong Curvature

A finite-volume method for three-dimensional, steady, incompressible flows in complex geometries is presented. The method uses generalized Body-Fitted Coordinates to accurately take into account the shape of the boundary. A collocated scheme is employed, which uses the three covariant velocities and the pressure as main variables. Continuity is coupled with the momentum equations using the SIMPLEC algorithm. It is found that the SIMPLEC algorithm can provide savings in computational time of up to 40 percent compared to calculations with SIMPLE. Sensitivity studies are also performed to find optimum values of the underrelaxation parameters. The method is validated against experimental results for the case of the flow in a 90 deg curved duct of square cross-section and comparatively strong curvature. The application of the method to the prediction of flows in complex geometries is then illustrated.

Robust and Efficient Setup Procedure for Complex Triangulations in Immersed Boundary Simulations

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Jianming Yang ◽  
Frederick Stern
Keyword(s):  
High Resolution ◽  
Grid Point ◽  
Immersed Boundary ◽  
Complex Geometries ◽  
Immersed Boundary Methods ◽  
Ray Casting ◽  
Cartesian Grids ◽  
Triangulated Surfaces ◽  
Boundary Methods ◽  
Fast Procedure

Immersed boundary methods have been widely used for simulating flows with complex geometries, as quality boundary-conforming grids are usually difficult to generate for complex geometries, especially when motion and/or deformation is involved. A major task in immersed boundary simulations is to inject the immersed boundary information into the background Cartesian grid, such as the inside/outside status of a grid point with regard to the immersed boundary and the accurate subcell position of the immersed boundary for a grid point next to it. Complex geometries in immersed boundary methods can be conveniently represented with triangulated surfaces placed upon underlying Cartesian grids in a Lagrangian manner. Regular, intuitive implementations using triangulations can be error-prone and/or cumbersome in dealing with robustness issues. In addition, they can be prohibitively expensive for high resolution simulations with complex moving/deforming boundaries. In this paper, a simple, robust, and fast procedure is developed for setting up complex triangulations in immersed boundary simulations. Central to this setup procedure are a ray casting and closest surface point computation algorithms. Several illustrative examples, including high resolution cases with Cartesian grids of up to 2.1 × 109 points and triangulations of up to 1.3 × 106 surface elements, are performed to demonstrate the robustness and efficiency of our procedure.

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