Dynamic Mesh Preview Error in simulation of undulation motion using UDF!
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hi,moring everyone:
i am now implementing the simulation on sinusoidal undulation of fish with dynamic mesh technology in ANSYS FLUENT, the undulation function is imported into FLUENT with the macro DEFINE_CG_MOTION, and the udf can be successfully built and loaded. Now the problem is that the preview of dynamic mesh cann‘t be accomplished smoothly , the error dialogue box pops up once i click the "preview" botton, and at the same time ,the profile of fish changes in a very strange way: the two lines(white solid lines in the figure below) merge into a single line after previewing, and the error dialogue box is always poping up again after i click the OK botton, and i can still see the motion of fish (a singe line), i was so puzzled , is there any problem with my mesh or with my code? i will be really appreciated if anyone can provide some information, thanks again. appendixes are the initial status of hydrofoil and the status after clicking preview botton, respectively: |
:):)can anyone help me?
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hi everyone, now the error problem is solved by setting the interface circle and the corresponding internal domain as ""deforming" boundaries, and the mesh can be previewed , but the hydrofoil (two white solid lines) still merge into one single line once they start to undulate. DOES this imply that sth is wrong with my UDF:)?
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Hello
how in your opinion people can help you if you do not show any data. no case settings, no udf? Best regards |
Quote:
the undulation.c, a program of hydrofoil , can be expressed as follows: // #include "udf.h" #include "dynamesh_tools.h" #include "math.h" #define U 40.05 #define L 1.00 #define a0 0.02 #define a1 0.08 #define a2 0.16 DEFINE_GRID_MOTION(undulation005_fish, domain, dt, time, dtime) { Thread *tf = DT_THREAD(dt); /* pointer to a thread*/ face_t f; int n; Node *node_p; real A, x, y, wave, sign; real St = 0.05; /* set deforming flags */ SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf)); begin_f_loop(f, tf) { f_node_loop(f, tf, n) { node_p = F_NODE(f, tf, n); if (NODE_POS_NEED_UPDATE(node_p)) { NODE_POS_UPDATED(node_p); x = NODE_X(node_p); A = a0 - a1*x + a2*x*x; wave = 2 * M_PI / L; sign = x - St * U * time; y = A * sin(wave*sign); NODE_Y(node_p) = y; } } } end_f_loop(f, tf); } |
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and chose "Smoothing and Remeshing" as the mesh update methods, the corresponding settings are displayed below:
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:):)can anybody help me, please?
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Hello!...Did you solved your problem?....I am simulating the same case of you
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They answered already. You have to use DEFINE_GRID_MOTION() macro, you can find the code in early replies
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I have compiled the same UDF and it worked!....But still facing the same problem of two lines merging....If anyone solved this problem can suggest me a solution?
Thanks in advance |
:confused:I have the lines merging problem as well.
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