{"id":382543,"date":"2024-09-12T18:59:16","date_gmt":"2024-09-12T18:59:16","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/382543\/"},"modified":"2024-09-13T11:31:23","modified_gmt":"2024-09-13T11:31:23","slug":"382543","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/382543\/","title":{"rendered":"Reply To: ICFD Extremely high and constant drag pressure forces"},"content":{"rendered":"

<p> <\/p><p>Hello Reno,<br><br>Thank you for your fast response. I am answering your questions below:<br><br>1.<\/strong> I am using version mpp d R13, revision R13.1.1-17-ga451ec960f<br><br>2. <\/strong>I have run the cylinder example without changing any input data (Re = 100, right?). At 50s, on the icfdragi.dat I get the following forces:<br>Fpx = -2.622783E-01    Fpy = 9.907471E-02  Fvx = -8.534790E-02   Fvy = 1.326471E-02<\/p><p>Which is: Fx = 0.347N (cD = 3.53) and Fy = 0.112N (cL = 1.14). From the icfdraga.dat i get simillar forces on x and considerably lower on y<\/p><p>This does not correlate with page 10 of the pdf that you have attached. Let me know what do you think, as it might be that I am not looking to the correct data.<\/p><p>3. <\/strong>At 10m\/s I already have pressures of 2e6 (very homogeneous). At 56m\/s, I have pressures that vary between 3.5e6 and 7.5e5. Pressure distribution however makes sense qualitatively. According to published data, pressures should be between 6e3 and 2e4 <\/p><p>This makes me think that there is some kind of initial pressure on the model, but the only pressure-related input\/boundary condition is at the output surface with *ICFD_BOUNDARY_PRESCRIBED_PRE.<\/p><p>4.<\/strong> I have run the model applying a freeslip condition in the body surface. Now I don’t get any viscosity forces in both icfdraga.dat and icfdragi.dat. Pressure forces are simillar between files, and have decreased by 14% aprox in all x, y and z axes compared with non-slip simulation. But still, they remain in the range of <span class=””katex””><span class=””katex-mathml””>10^4\/10^5<\/span><\/span>, when they should be in the range of <span class=””katex””><span class=””katex-mathml””>10^2\/10^3<\/span><\/span>.<br><br>I hope this helps. Thank you very much,<br>Arnau<\/p><p> <\/p><\/p>\n","protected":false},"template":"","class_list":["post-382543","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t