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发表于 2010-4-28 14:18:52
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来自 甘肃兰州
我使用的是level set方法。
看到帮助文档里有这个,不知道能否解决收敛问题。
Convergence Problems
If you run into convergence problems, check the following:
• Is γ approximately as large as the maximum speed of the flow?
• Is ε constant and equal in all subdomains passed by the interface?
• Is ε at least as large as half the maximum element size in the region passed by the interface?
• Is the cell Reynolds number smaller than 2? If not you should use artificial diffusion. Open the Artificial Diffusion dialog box by clicking the corresponding button on the Sources/Sinks page of the Subdomain Settings dialog box. Click the Navier-Stokes Equations tab. Apply anisotropic diffusion for the Navier-Stokes equations by selecting the Streamline diffusion check box and then selecting Anisotropic diffusion from the list next to the check box. If the convergence problems persist, and increasing the resolution is not possible, apply isotropic diffusion as well.
• If the effect of surface tension is small, set the surface tension coefficient σ to zero.
• Make sure you have initialized the level set function as described in the section “Solution Procedure” on page 32.
• Verify that there is no inflow through any boundaries that has been specified as outlet boundaries. For boundaries that are both inlets and outlets, specify them as inlets.
• If the pressure is not specified on any boundary, make sure that there is either a condition on the pressure in one point or a condition on the integral of the pressure over the entire fluid domain.
• If you have a velocity boundary condition, increase it gradually from zero to its actual value during a short initial time interval using the built-in Heaviside smoothing function flc1hs(t-deltat,deltat). |
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