# sliding mesh, confused me, help! help！

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 July 8, 2009, 04:33 sliding mesh, confused me, help! help！ #1 New Member   Wei Yang Join Date: Jul 2009 Location: Shanghai Posts: 4 Rep Power: 16 Hi,all: In CFD simulation for an airfoil, we usually give a velicoty in let and let the airfoil static. Now, I am doing a cfd simulation that let the air stable, the airfoil slids in a box. Yes, dynamic mesh method can do it. But I want to resolve it by using the sliding mesh method, for there are some articles describing studies for car and train in crossing action. When I set up the sliding mesh and run FLUENT, I found the box at which the airfoil is has a velocity specified for the airfoil wholly. While what I want is the airfoil has a velocity and moves forwards, the air around is static. Does the velocity of sliding mesh mean the velocity of each fluid element in that mesh? In another word, if one part of mesh is sliding at velocity V, is the fluid in that mesh also moving at velocity V? thanks!

 September 22, 2009, 22:14 #2 New Member   Wei Yang Join Date: Jul 2009 Location: Shanghai Posts: 4 Rep Power: 16 I have found the key. A stable result is need before carry sliding mesh simulation. And yes, the stable initialization means the whole flow holds a velocity of zero. Then let the sliding mesh work. It does work. The result brings some other question. The lift and the drag is not good,there is some difference from results of conventional CFD study. __________________ Wei Yang Ph.D. student Shanghai Automotive Wind Tunnel Center Tongji University Shanghai 201804 P.R. China

 September 30, 2009, 22:45 #3 Senior Member     YH Tan Join Date: Mar 2009 Location: Malaysia Posts: 119 Rep Power: 16 Your simulation on sliding mesh is interesting. I guess ur using the air above and below the airfoil to slide and have the mesh periodic. am i right? Can you share some of ur picture of simulation? u said there is differences with conventional CFD study, what is the difference? __________________ Herntan, Add Reputation if I am right