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-   -   Nose singularity of blunt body grids (https://www.cfd-online.com/Forums/main/3243-nose-singularity-blunt-body-grids.html)

 Stefan Maehlmann March 16, 2001 04:11

Nose singularity of blunt body grids

Hello,

when generating grids for symmetric blunt bodies (one block) a singularity is imposed at the nosetip. My question is if there is a way to get rid off this singularity or simplify somehow the treatment of this single point in the code.

 Brian Gribben March 16, 2001 08:01

Re: Nose singularity of blunt body grids

Ah, this can be a bit of a problem. Here's how I've seen it done before.

Just use your normal grid format ( I assume you're using 3-D structured grids ). For the grid cells at the singularity, they will have one side collapsed to a line, in effect a five-sided rather than a six-sided cell. The trick is to still treat it as a normal six-sided cell, don't bother treating it as a special case. Just make sure that when you are calculating the area of this (collapsed) face you get a zero value, then ensure that this results in a zero flux contribution across that face. This may be a bit tricky if you have a viscous scheme but if you stick to the principle you should be ok : don't invent special treatments, just make sure your normal treatment does the right thing when it finds a zero cell area. It's hard to be more specific since different codes work out fluxes in different ways.

I hope that helps.

 Erich Kreiselmaier March 19, 2001 11:18

Re: Nose singularity of blunt body grids

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