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January 29, 2020, 03:12 
UDF for blade displacement

#1 
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Hi my friends ... I need to write a UDF for a blade displacement ... I should define Phi (as the picture below eq 11) to use it in another formula( as the picture below eq 10), but I can't make a loop over x to define Phi to use it! it is always one number(number 1.695913)!
here is my UDF ... #include "udf.h" #define PI 3.141592654 #define ID 3 real xold=0.0;real yold=0.0; real uold=0.0;real vold=0.0; real dx=0.0e0;real dy=0.0e0; real L=0.03; real Phi; DEFINE_EXECUTE_AT_END(ForceCalculate) { real Fy=0.0e0; real x[ND_ND]; real yy; #if !RP_HOST /* SERIAL or NODE */ real NV_VEC(WS); real area[ND_ND]; real Fpy = 0.0; real Fvy=0.0; Domain *d= Get_Domain(1); Thread *t=Lookup_Thread(d,ID); face_t f; begin_f_loop(f,t) { F_CENTROID(x,f,t); yy=x[0]; Phi = 1sin(((90*PI)/180)*(yy/L)); } end_f_loop(f,t); begin_f_loop(f, t) if (PRINCIPAL_FACE_P(f,t)) { F_AREA(area,f,t); Fpy+=L*area[1]*F_P(f,t)*Phi; } end_f_loop(f, t) Fy = Fpy; #if RP_NODE /* Perform node synchronized actions here*/ Fy=PRF_GRSUM1(Fy); Fx=PRF_GRSUM1(Fx); #endif /* RP_NODE */ #endif /* !RP_HOST */ // Message0(" k=%g wd= %g Fy=%g\n",k,wd,Fy); // Message0(" time=%g xold= %g deltaT=%g\n",time,xold,ts); node_to_host_real_2(Fy,Fx); /* Does nothing in SERIAL */ #if !RP_NODE /* SERIAL or HOST */ real C=3.69e6; real teta=1.38e9; real my=7.789e0; real kyy=3.6; real ky=kyy+((teta*teta)/C); real zety=0.0; // real wny=sqrt(ky/my); real cy=2.0e0*my*wny*zety; real wdy=wny*sqrt(1.0e0zety*zety); // real ts=CURRENT_TIMESTEP; real time=CURRENT_TIME; // real Ay,By,y; Ay=yoldFy/ky; By=(vold+zety*wny*Ay)/wdy; y=exp(zety*wny*ts)*(Ay*cos(wdy*ts)+By*sin(wdy*ts))+Fy/ky; vold=zety*wny*(yFy/ky)+wdy*exp(zety*wny*ts)*(By*cos(wdy*ts)Ay*sin(wdy*ts)); dy=yyold; yold=y; // // FILE *fout; fout = fopen ("data2D.out","a"); fprintf(fout," %f %f %f %f %f\n",time,yold,Fy,vold,Phi); fclose(fout); #endif /* !RP_NODE */ } 

January 29, 2020, 08:01 
Phi is a scalar

#2 
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It gives only one value for Phi because Phi is declared as a scalar, i.e., it can store only one number. What you need is a vector that can store as many values of Phi as many x are there. Recommended to use UDM in place of Phi.
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January 29, 2020, 08:07 
how can I do?

#3 
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Thanks for your accountability, since I am poor at writing a UDF and my information is not high, can you correct this for me?


January 29, 2020, 08:10 
Suggestions

#4 
Senior Member

You should replace Phi with F_UDMI(f, t, 0) everywhere in the code. Along with that you also need to ensure that you enable one UDM in Fluent and initialize by patching it to 0. UDMs are available at UDFs > Memory.
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January 29, 2020, 08:45 

#5 
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again really Thank you ... to be sure that everything is ok, I want to see the Phi data in **fprintf(fout," %f %f %f %f %f\n",time,yold,Fy,vold,Phi);** as I replace the Phi with F_UDMI(f, t, 0), how can I do it?


January 29, 2020, 08:49 
Write inside the loop

#6 
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Since Phi is not a single value, you have write your output file within the face loop. And as usual, replace Phi with UDM.
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January 29, 2020, 09:07 

#7  
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Quote:
I know I am a bad student!!! here is my improved UDF: Is it ok?!!!! #include "udf.h" #define PI 3.141592654 #define ID 3 real xold=0.0;real yold=0.0; real uold=0.0;real vold=0.0; real dx=0.0e0;real dy=0.0e0; real L=0.03; DEFINE_EXECUTE_AT_END(ForceCalculate) { real Fy=0.0e0; real x[ND_ND]; real yy; #if !RP_HOST /* SERIAL or NODE */ real NV_VEC(WS); real area[ND_ND]; real Fpy = 0.0; real Fvy=0.0; Domain *d= Get_Domain(1); Thread *t=Lookup_Thread(d,ID); face_t f; begin_f_loop(f,t) { F_CENTROID(x,f,t); yy=x[0]; F_UDMI(f, t, 0) = 1sin(((90*PI)/180)*(yy/L)); } end_f_loop(f,t); begin_f_loop(f, t) if (PRINCIPAL_FACE_P(f,t)) { F_AREA(area,f,t); Fpy+=L*area[1]*F_P(f,t)*F_UDMI(f, t, 0); } end_f_loop(f, t) Fy = Fpy; #if RP_NODE /* Perform node synchronized actions here*/ Fy=PRF_GRSUM1(Fy); Fx=PRF_GRSUM1(Fx); #endif /* RP_NODE */ #endif /* !RP_HOST */ // Message0(" k=%g wd= %g Fy=%g\n",k,wd,Fy); // Message0(" time=%g xold= %g deltaT=%g\n",time,xold,ts); node_to_host_real_2(Fy,Fx); /* Does nothing in SERIAL */ #if !RP_NODE /* SERIAL or HOST */ real C=3.69e6; real teta=1.38e9; real my=7.789e0; real kyy=3.6; real ky=kyy+((teta*teta)/C); real zety=0.0; // real wny=sqrt(ky/my); real cy=2.0e0*my*wny*zety; real wdy=wny*sqrt(1.0e0zety*zety); // real ts=CURRENT_TIMESTEP; real time=CURRENT_TIME; // real Ay,By,y; Ay=yoldFy/ky; By=(vold+zety*wny*Ay)/wdy; y=exp(zety*wny*ts)*(Ay*cos(wdy*ts)+By*sin(wdy*ts))+Fy/ky; vold=zety*wny*(yFy/ky)+wdy*exp(zety*wny*ts)*(By*cos(wdy*ts)Ay*sin(wdy*ts)); dy=yyold; yold=y; // // FILE *fout; fout = fopen ("data2D.out","a"); fprintf(fout," %f %f %f %f %f\n",time,yold,Fy,vold,F_UDMI(f, t, 0)); fclose(fout); #endif /* !RP_NODE */ } 

January 30, 2020, 03:08 

#8 
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Alexander
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compile code
Code:
#include "udf.h" #define PI 3.141592654 #define ID 3 real xold=0.0;real yold=0.0; real uold=0.0;real vold=0.0; real dx=0.0e0;real dy=0.0e0; real L=0.03; DEFINE_EXECUTE_AT_END(ForceCalculate) { real Fy=0.0e0; real x[ND_ND]; real yy; real C=3.69e6; real teta=1.38e9; real my=7.789e0; real kyy=3.6; real ky=kyy+((teta*teta)/C); real zety=0.0; // real wny=sqrt(ky/my); real cy=2.0e0*my*wny*zety; real wdy=wny*sqrt(1.0e0zety*zety); // real ts=CURRENT_TIMESTEP; real time=CURRENT_TIME; // real Ay,By,y; FILE *fout; real NV_VEC(WS); real area[ND_ND]; real Fpy = 0.0; real Fvy=0.0; Domain *d= Get_Domain(1); Thread *t=Lookup_Thread(d,ID); face_t f; begin_f_loop(f,t) { F_CENTROID(x,f,t); yy=x[0]; F_UDMI(f, t, 0) = 1sin(((90*PI)/180)*(yy/L)); } end_f_loop(f,t); begin_f_loop(f, t) if (PRINCIPAL_FACE_P(f,t)) { F_AREA(area,f,t); Fpy+=L*area[1]*F_P(f,t)*F_UDMI(f, t, 0); } end_f_loop(f, t) Fy = Fpy; #if RP_NODE /* SERIAL or NODE */ Fy=PRF_GRSUM1(Fy); #endif /* RP_NODE */ // Message0(" k=%g wd= %g Fy=%g\n",k,wd,Fy); // Message0(" time=%g xold= %g deltaT=%g\n",time,xold,ts); node_to_host_real_1(Fy); /* Does nothing in SERIAL */ #if !RP_NODE /* SERIAL or HOST */ Ay=yoldFy/ky; By=(vold+zety*wny*Ay)/wdy; y=exp(zety*wny*ts)*(Ay*cos(wdy*ts)+By*sin(wdy*ts))+Fy/ky; vold=zety*wny*(yFy/ky)+wdy*exp(zety*wny*ts)*(By*cos(wdy*ts)Ay*sin(wdy*ts)); dy=yyold; yold=y; // // fout = fopen ("data2D.out","a"); fprintf(fout," %f %f %f %f %f\n",time,yold,Fy,vold,F_UDMI(f, t, 0)); fclose(fout); #endif /* !RP_NODE */ }
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January 30, 2020, 04:45 
Segmentation Violation Expected

#9 
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The code that Alexander shared will work for most of the part; I haven't checked it line by line but most likely it will do most of the work, except for writing. You should get Segmentation Violation while writing the output since f does not exist outside begin_f_loop. Therefore, any command making use of f has to be within the loop.
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January 30, 2020, 05:14 

#10  
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Quote:
in the links I send you my Mesh, My output Data and my article I am working on! my last Target is to simulate the blade displacement! http://s7.picofile.com/file/83865613..._yeki.msh.html http://s6.picofile.com/file/8386561326/data2D.out.html http://s7.picofile.com/file/83865613...rials.pdf.html 

January 30, 2020, 05:21 

#11 
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yeah! this writes the F_UDMI(f, t, 0) by zero, I am really Tired by this! can I have Conversation with you in private! I will send you my article I am working on it! maybe you can help me... this is more than 3 month I am working on this UDF


January 30, 2020, 06:42 
Not working part

#12 
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Which part of the UDF is not working. About writing I know it will not work but the solution is simple; just do writing within the loop, i.e., move the line with command fprintf before the end_f_loop. Is there any other issue with it?
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January 30, 2020, 08:53 

#13  
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Quote:
how can I make a grid motion to simulating the blade displacement?! with use of the function in the picture: yt is yold in my code and Phi is F_UDMI(f, t, 0) 

January 30, 2020, 09:49 
Define_grid_motion

#14 
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Look for DEFINE_GRID_MOTION example in UDF manual
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January 30, 2020, 12:36 

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January 31, 2020, 04:18 
Use UDM

#16 
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For all those variables that are varying with space, i.e., functions of their position, it is recommended to use UDM. It appears that yold is also a function of position. Therefore, you should invoke another UDM, and use F_UDMI(f,t,1) to store the value and then use same UDM in GRID_MOTION
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