OpenFOAM (SimFlow) Query: Calculating Drag Coeff's

_Ennui · August 31, 2016, 12:13

Evening all,

As SimFlow is just OpenFOAM but pretty, and there is a lack of a specific SimFlow forum I thought that this would be the most appropriate place to ask. I hope this is correct.

I am currently attempting to calculate Cd for a simple cylinder, I'm using the pisoFoam solver. The cylinder is fully submerged in sea water (which i have inputted as a new material - listing values for density and dynamic viscosity). I then set the case to monitor the Force Coefficients, but the density is never required as an input.

I am extremely confused as to how the software is generating a value for Cd without using the fluid density for sea water that I have inputted.

Any help would be greatly appreciated, I have a feeling I may be being extremely stupid and overlooking something completely obvious. If there is any further information / clarification required please just ask.

Cheers in advance.

_Ennui · September 1, 2016, 04:54

Found a bodge (i think), by editing the value of "rhoInf" in the case controlDict to the required value should resolve the problem.

My question remains, if anyone knows; if I input a new material using the terminology used in the material database for default materials (i.e. rho as the name for density) will the software automatically interpret this and change the material properties accordingly?

August 31, 2016, 12:13	OpenFOAM (SimFlow) Query: Calculating Drag Coeff's	#1
_Ennui New Member Join Date: Aug 2016 Posts: 9 Rep Power: 9	Evening all, As SimFlow is just OpenFOAM but pretty, and there is a lack of a specific SimFlow forum I thought that this would be the most appropriate place to ask. I hope this is correct. I am currently attempting to calculate Cd for a simple cylinder, I'm using the pisoFoam solver. The cylinder is fully submerged in sea water (which i have inputted as a new material - listing values for density and dynamic viscosity). I then set the case to monitor the Force Coefficients, but the density is never required as an input. I am extremely confused as to how the software is generating a value for Cd without using the fluid density for sea water that I have inputted. Any help would be greatly appreciated, I have a feeling I may be being extremely stupid and overlooking something completely obvious. If there is any further information / clarification required please just ask. Cheers in advance.

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September 1, 2016, 04:54		#2
_Ennui New Member Join Date: Aug 2016 Posts: 9 Rep Power: 9	Found a bodge (i think), by editing the value of "rhoInf" in the case controlDict to the required value should resolve the problem. My question remains, if anyone knows; if I input a new material using the terminology used in the material database for default materials (i.e. rho as the name for density) will the software automatically interpret this and change the material properties accordingly?