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Old   August 25, 2011, 03:07
Default Sand Grain Roughness
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Zhang Yang
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Hello, everybody

Does anybody know the definition of Equivalent Sand Grain Roughness? How does it relate to the real roughness of a material?

For example, if i know the real roughness of a material, how should i set the sand grain roughness for simulating a friction wall in CFX?

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Old   August 30, 2011, 03:11
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that depends on how your "real roughness" was determined and what data you have available (Ra, Rz, some older type ...).

there won't be a single, precise answer, i can tell you that
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