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calculate drag coefficient for body moving in waves |
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February 13, 2017, 07:00 |
calculate drag coefficient for body moving in waves
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#1 |
Member
Mona
Join Date: Mar 2016
Location: Berlin
Posts: 49
Rep Power: 10 |
Dear all,
I am trying to calculate the drag coefficient for a body, that is doing a pitch motion in regular waves. (I attached a sketch to give you an idea of the setup.) Drag coefficient: cd=2*Fd/(rho*U*|U|*A) Fd: Drag force, calculated with forces function A: reference area rho: density I figured that I can't use the forceCoeffs function, because U is not the free stream velocity in this case, but the relative velocity between the body and the fluid particles. So the velocity I need here is U=u(t)-v(t), where u(t) is the flow velocity in drag direction (x) and v(t) the velocity of the body, also in x-direction. (Please correct me if I am wrong here) Now I am wondering if any of you have some advice how to obtain those two values. 1)u(t) This value varies throughout the flow filed around the body, so should I set several probes and then take an average value or try to pick a characteristic point? 2)v(t) I am already outputting the angular velocity omega of the body. With v=omega*radius I will obtain the tangential velocity. But how can I obtain the x-component from that? My plan is to calculate cd(t) in postprocessing with all these above values. Any suggestions on how to do this are very appreciated! Cheers, Mona |
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May 20, 2017, 03:56 |
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#2 |
New Member
raju ram bhakar
Join Date: May 2017
Posts: 11
Rep Power: 9 |
Hello Mona,
I am visualising the motion of DTC Hull in FoamExtend using groovyBC and InterIbFoam. But I'm not able to visualise the flow around the hull geometry. Basically I don't know how to post process the available data and generate animations. When I open paraView using paraFoam there is region named as hull but when I use apply button there is no hull geometry of hull. How should I proceed with it please give some suggestion Thankyou. |
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