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Incylinder Dynamic Mesh Creating Negative Volume

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Old   July 12, 2006, 21:18
Default Incylinder Dynamic Mesh Creating Negative Volume
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Hi, I am Sujith, doing a academic project in Combustion of Diesel Engines. I created the mesh and fed the dynamic mesh parametrs, my starting crank angle is 360, speed is 2100rpm, Crank Step size (deg) is 0.2, Piston Stroke is 118mm and Connecting rod length is 220mm. The Dynamic mesh is moving from TDC to BDC (540deg) and when it is going back, at 641.2 deg, it is creating NEGATIVE VOLUME..!

Can anyone help me by providing informations about this problem and why it is happening?


Thanks in advance.

Regards, Sujith
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Old   July 20, 2006, 16:15
Default Re: Incylinder Dynamic Mesh Creating Negative Volu
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After it fails.. display the grid.. usually you could see where the negative volume is located because of gross deformation.
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Old   July 22, 2006, 11:17
Default Re: Incylinder Dynamic Mesh Creating Negative Volu
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Hi Sujtih

I am also facing a simillar problem, can you tell me how to fix it?

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Old   August 1, 2006, 15:53
Default Re: Incylinder Dynamic Mesh Creating Negative Volu
Curtis M Schreiber
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Hi, My associate and I encountered a situation similiar to this in an internal combustion engine cycle. The solution(s)for this case were: 1. Start at TDC, so that FLUENT is "creating" cells. 2. Use a structured mesh anywhere where the piston is moving. For our case it was simple to apply a structured mesh since it was just a cylinder, but yours may be different.

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