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-   -   Ship self propulsion simulation using Virtual Disk in Star CCM+ (https://www.cfd-online.com/Forums/star-ccm/236268-ship-self-propulsion-simulation-using-virtual-disk-star-ccm.html)

sumon May 21, 2021 12:19

Ship self propulsion simulation using Virtual Disk in Star CCM+
 
Dear Sir,
I'm currently working on a project where I'm trying to simulate the self-propulsion of a ship using virtual disk model. To obtain self-propulsion point for a particular speed, I have ran the simulation changing the disk rpm and obtained the rpm for which the net force in x direction zero (0) but at this point the advance ratio, J gives the velocity of advance (Va) equal to the inlet velocity (model velocity, Vm); This leads wake fraction 0. I am not sure whether it is right or wrong.

1. Can anyone please help me whether it is obvious or not? I am confused.
2. Another question, is there any alternative way to find out effective wake from the contour of the ratio of Axial Velocity to Model Velocity at the virtual disk plane? or How to find the inflow axial velocity on the virtual disk plane ?

Your kind responses would be very helpful for me.

a.gmira May 10, 2023 11:39

Good afternoon,

I am having the same problem. I am doing Thrust Identity to calculate the effective wake fraction but it gives me a value of zero. The pressure and velocity fields look ok so the wake fraction can not be zero.

Is it possible to calculate the effective wake fraction from the virtual disk model as I am doing?

Thank you very much in advance.

Kind regards,

A.gmira


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