negative DRAG,LIFT and MOMENT Coefficient,net mass flow rate is NOT ZERO...?
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hello every one,i'm using turbulence model k-omega sst,im trying to simulate 3D model ship in viscous flow under open channel wave BC,multiphase,
Domain- X: -183m and 173m. Y: -37.13m and 37.12m. Z: -22.23539m and 18.9m. ship size- L-65m. B-15m. H-6m. mesh size near ship 2m and far away 6m. least mesh quality 0.5342 out of 1, solver-pressure based,absolute,steady,gravity. models-multiphase:VOF,open channel flow,open channel wave BC,implicit.viscous:k-omega SST. phase:air and water. BC:inlet=turbulence intensity 5% and turbulence length scale (.07*L).L-hydraulic diameter=6.31.(L=4*A/P),Area and perimeter.velocity 4m/s. open channel Wave BC-2nd order stokes,shallow/intermediate waves,time period 4 sec,amplitude-1m wavelength 24.98m,phase angle zero. oulet= backflow turbulence intensity 5% and turbulence length scale .4417(I HAVE DOUBT ABOUT THIS THINK) Solution method: SIMPLE gradient-least squares cell based. pressure- PRESTO momentum-2nd order upwind Volume Fraction-BGM and other are 2nd order upwind solution control defualt, only max turbulence Viscosity ratio 1*e18. initilization from inlet, But im getting negative Drag, Lift and moment coefficient.net mass flow rate is not zero,reverse flow.......suggestion please Guys. |
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