[armanss]

hi
im working on a boat in regular wave with DFBI morphing motion and i have 2 problem in running
1. in the output window i have an error 'Reversed flow on X faces on Block.out' and 'Turbulent viscosity limited on X cells in Subtract' and after a while the run will stop

2. and some times the error '###morpher : corrector size is large (XXX) and it may take long time to finish' appear and the run will stop

Does anyone know how I fix these problems?

[fluid23]

the reversed flow warning is a product of your domain/boundary conditions. typically you want to avoid this, but there are some instances where it is acceptable. basically, it is telling you that the 'out' boundary in region 'block' is too close to your areas of interest in the domain causing recirculation. you will either need to revise your geometry or extrude this boundary to avoid recirculation.

the turbulent viscosity warning is a hard limit that is designed to reduce the risk of divergence by limiting turbulent viscosity to some value. if it is appearing over and over again, you likely have a mesh issue. there are other things that could potentially cause this, but given your application I suspect your mesh needs to be fixed.

I have never seen issue 2 before, but I bet if you fix the other two it will go away. I believe there is a DFBI tutorial on this very situation documented in the help. I suggest you try that before doing your own analysis, if you haven't already done so.

[armanss]

Originally Posted by MBdonCFD

the reversed flow warning is a product of your domain/boundary conditions. typically you want to avoid this, but there are some instances where it is acceptable. basically, it is telling you that the 'out' boundary in region 'block' is too close to your areas of interest in the domain causing recirculation. you will either need to revise your geometry or extrude this boundary to avoid recirculation.

the turbulent viscosity warning is a hard limit that is designed to reduce the risk of divergence by limiting turbulent viscosity to some value. if it is appearing over and over again, you likely have a mesh issue. there are other things that could potentially cause this, but given your application I suspect your mesh needs to be fixed.

I have never seen issue 2 before, but I bet if you fix the other two it will go away. I believe there is a DFBI tutorial on this very situation documented in the help. I suggest you try that before doing your own analysis, if you haven't already done so.

thank you for your guidance