visualization of cavitation on propeller blades
hi..
how can i visualize the cavitation on propeller blade surface especially vapor/bobble occurrence on surface where cavitation exists? is a CFD-post software necessary for that? thanks, emreg |
Assuming that you have used the mixture model coupled with one of the cavitational models, you have only to plot contour of vapor fraction of secondary phase (vapor).
Daniele |
hi
residual vf-phase-2 appears allways zero during whole of the transient iteration other residuals change meaningly. i dont know why vf-phase-2 doesnt change could u help me plz |
Vapor residual is 0 because in your simulation cavitation doesn't occour for some reasons:
- Are you sure that cavitation occurs? what is your cavitation number? - What are your boundary conditions? - What is the quality of your mesh? - What time step are you using for the transient cavitation? In my experience you have to use a good quality mesh, with appropriate cell size able to capture cavitation; also you have to use small time step (I often used 10^-6 - 10^-7 s). |
hi,
i hav an 10 million tetra mesh >>> 2 million polihedral. i visualize vapor fraction by displaying contours, it solved cavitation already, but vf-phase 2 still remains zero. pfff. time step : 1 degree. .. |
Cavitation isn't solved if vapor fraction is 0; this means that cavitation doesn't occur in your simulation.
Explain your case: - are you moving the blade?I haven't experience with moving frames, I only simulated cavitation (steady and transient) by moving the liquid. - If you are moving the blade, what is the rpm value?For example, if your blade is at 30 rpm you have 180 degree per second, this means that 1 degree is accomplished in 5.55e-3 s..I recommend to low this value till 10^-5 - 10^-6. - I recommend to check your grid and to size cells where you think that cavitation occurs near 0.125 mm3 (tet size near 0.5 mm). |
i didnt say vapor fraction is zero..
i am talking about vapor phase 2 Residual... it remains zero.. observing vapor. |
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