An adaptive vortex method for two-dimensional viscous and incompressible flows
The thesis is centered around an adaptive method for calculating vorticity dominated flows in two dimensions. The authors uses the vortex method after a general transformation is applied to the flow region because the vortex elements describe the local flow more accurately if the transformation is suitably chosen. A good example of this is boundary layer flow, where vortex sheets serve to represent the vorticity as long as the Prandtl equation holds, but the method is inaccurate in the region where transition from Prandtl to fall Navier-Stokes equations occurs. Physical intuition tells us that the transition should be a natural process and therefore should be smooth, depending fully on the local flow and geometry. It is shown that this can be realized with a good spatial transformation which takes account of the above factors. In the special case of finite-area vortex regions and within 1st-order accuracy, the Biot-Savart law is explicit and equivalent to the elliptic vortex method with the axes ratio and orientation evolving according to the continuous transformation. The transformation is obtained from the real flow by averaging, truncation and satisfying the same boundary condition as the real flow. Some experiments for typical flows are carried out in detail. He also modeled a two-dimensional, dilute fluid-particle system with low Reynolds number flow around cylindrical particles and high Reyonlds number with respect to the bulk flow. Full particle methods are used to solve both the fluid and particle phase flows. The vortex method is used for the nearly incompressible fluid phase. The compressible particle phase is taken care of by using Voronoi diagrams suitably. On the microscopic scale the Stokes-Oseen formula is used to represent the forces on particles.
- Research Organization:
- New York Univ., NY (USA)
- OSTI ID:
- 6095109
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420400 -- Engineering-- Heat Transfer & Fluid Flow
640410* -- Fluid Physics-- General Fluid Dynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOUNDARY LAYERS
CALCULATION METHODS
COMPARATIVE EVALUATIONS
FLUID FLOW
INCOMPRESSIBLE FLOW
LAYERS
NUMERICAL SOLUTION
REYNOLDS NUMBER
TWO-DIMENSIONAL CALCULATIONS
TWO-PHASE FLOW
VISCOUS FLOW
VORTICES