6DOF solver (buoyancy and hydrostatic force)
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Hi all,
I am a relatively new Fluent user and am trying to simulate a floating object in water with a regular wave input. I am attempting to use the 6DOF solver to set the properties of the object such as mass, moments of inertia, and a spring damper system to represent a tether. My question is how I deal with the hydrostatic force that acts on the object. As this force is quite large, will it effect my object's or is it ignored by the 6DOF solver? Do I need to remove the value of the hydrostatic force by using an equal and opposite external force acting on the body with prop[SDOF_LOAD_F_Y]? Additionally, is buoyancy automatically included in the 6DOF solver? Or do I need to include this buoyancy force also with prop[SDOF_LOAD_F_Y]? I have attached the UDF but it may be difficult to follow, let me know if more info is needed. Thanks in advance for the help, -Zac |
Quote:
in 6DOF, the solver take the hydrostatic force but any other force due to the gravity for exemple without you indicate a gravity field in fluent. whats more in your UDF, there is a thing that I think it s wrong. Code:
for(i=0;i<3;i++) for i = 0 x_cg[0]=DT_CG(dt)[0]; v_cg_x = xcg[0]-xcg[-1] for i = 1 x_cg[1]=DT_CG(dt)[1]; v_cg_x = xcg[1]-xcg[0] for i = 2 x_cg[2]=DT_CG(dt)[2]; v_cg_x = xcg[2]-xcg[1] for i = 3 x_cg[3]=DT_CG(dt)[3]; v_cg_x = xcg[3]-xcg[2] But 0 correspond to x-axis 1 correspond to y-axis 2 correspond to z-axis 3 correspond to nothing instead of taking the value of positionog your gravity center in the previous time step. |
Hi guys,
Probably it is too late now, but I am also testing a body movement inside a fluid (water) and it seems like buoyancy is not automatically included, just like Zachary described. I suppose this can be very tricky in cases including dynamic variation of wetted volume. I my case the body free vibration is much less damped than I expected. Any tips? |
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