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- - **calculating the face gradient of a UDS in fluent**
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calculating the face gradient of a UDS in fluentHi every one,
I am trying to solve water transport equation in a fuel cell using ANSYS Fluent. I need to define a flux for the equation that I am gonna solve. The problem is that I cannot calculate face gradients in my code. I used F_UDSI_G(c,t,0) macro for this purpose but I recieved this error: " ..\..\src\sources2.c(348) : error C2109: subscript requires array or pointer type ..\..\src\sources2.c(348) : error C2109: subscript requires array or pointer type ..\..\src\sources2.c(348) : error C2109: subscript requires array or pointer type " Does anybody know how to calculate face gradients of a UDS in fluent? |

I think that gradient data are not stored for the faces excepted boundary faces. You can only calculate the gradient by estimating a mean of the adjacent cells to the face....
Good luck |

Hi every body
I wanted to return derivative of UDS as wall boundary value, but I faced with "fatal signal" while initializing (both Hybrid and standard) that I found this because of boundary condition UDS.:( this is part of my udf for B.C of UDS( volume fraction of nanoparticle in my case) DEFINE_PROFILE(alpha_bc1,thread,position) { Thread *t; cell_t c; . . . begin_f_loop(f,thread) { C_UDSI_G(c,t,0)[0]=-(D_T/D_B)*C_T_G(c,t)[0]; F_PROFILE(f,thread,position)=C_UDSI_G(c,t,0)[0]; } end_f_loop(f,t) } I would appreciate if anyone can help me about my mistakes. |

Furthermore, I used Define_Adjust to calculate laplacian, maybe this is my fault?
can I use UDS as scalar variable and then I used it in source function? I will turn off all Uds except one that I wanted to solve. is it true? thread_loop_c(t,d) { begin_c_loop(c,t) { C_UDSI(c,t,1)=D_T*C_T_G(c,t)[0]; C_UDSI(c,t,2)=D_T*C_T_G(c,t)[1]; C_UDSI(c,t,3)=D_T*C_T_G(c,t)[2]; Laplacian=Laplacian+C_UDSI_G(c,t,1)[0]+C_UDSI_G(c,t,2)[1]+C_UDSI_G(c,t,3)[2]; C_UDSI(c,t,5)=dD_T*C_T_G(c,t)[0]; C_UDSI(c,t,6)=dD_T*C_T_G(c,t)[1]; C_UDSI(c,t,7)=dD_T*C_T_G(c,t)[2]; d_Laplacian=d_Laplacian+C_UDSI_G(c,t,4)[0]+C_UDSI_G(c,t,5)[1]+C_UDSI_G(c,t,6)[2]; C_UDSI(c,t,9)=D_D*C_T_G(c,t)[0]; C_UDSI(c,t,10)=D_D*C_T_G(c,t)[1]; C_UDSI(c,t,11)=D_D*C_T_G(c,t)[2]; LL=LL+C_UDSI_G(c,t,9)[0]+C_UDSI_G(c,t,10)[1]+C_UDSI_G(c,t,11)[2]; C_UDSI(c,t,13)=dD_D*C_T_G(c,t)[0]; C_UDSI(c,t,14)=dD_D*C_T_G(c,t)[1]; C_UDSI(c,t,15)=dD_D*C_T_G(c,t)[2]; dLL=dLL+C_UDSI_G(c,t,13)[0]+C_UDSI_G(c,t,14)[1]+C_UDSI_G(c,t,15)[2]; } end_c_loop(c,t) } C_UDSI(c,t,4)=Laplacian; C_UDSI(c,t,8)=d_Laplacian; C_UDSI(c,t,12)=LL; C_UDSI(c,t,16)=dLL; } |

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