{"id":356491,"date":"2024-03-11T19:45:45","date_gmt":"2024-03-11T19:45:45","guid":{"rendered":"\/forum\/forums\/topic\/unable-to-acheive-anticipated-static-and-total-pressure-values\/"},"modified":"2024-03-11T19:45:45","modified_gmt":"2024-03-11T19:45:45","slug":"unable-to-acheive-anticipated-static-and-total-pressure-values","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/unable-to-acheive-anticipated-static-and-total-pressure-values\/","title":{"rendered":"Unable to acheive anticipated Static and Total Pressure Values"},"content":{"rendered":"

Hello,<\/span><\/p>\n

I am an Ansys Workbench user, I am struggling to correctly predicit data with a fluent external subsonic aerodynamic flow case of a mini-jet engine. <\/span><\/p>\n

Below is the grid of the domain around (10m long by 20m wide) 500 times the diamter of the nozzle, i am trying to simulate with <\/span><\/p>\n

Total number of elements: 268,038<\/span><\/p>\n

Orthogonality: 0.49<\/span><\/p>\n

Skewness: 0.89  (<\/span>even if i had reduced the skeweness to 0.6 i had not seen any difference with the behaiour of the output paramters post simulation)<\/span> \"Mesh\"<\/p>\n

As you can see, I am running a steady, 2D-axisymmetric; density based solver, for ideal gas with energy equation, the turbulnce model being Realizable, k-e, scalable wall function.<\/span><\/p>\n

I tried the case where i would set the ambient pressure value at operating pressure and the gauge pressures are set to zero. this gives me results of the following …..  It is anticipated to have subsonic flow of Mach 0.7894 but fluent gives only 0.59, same with velocity, supposed to give around 480 m\/s but we get back 372m\/s, given all these parametrs are pressure dependent, i checked the Static and Total Pressure values, which also seemed to be extremely low and deviated. Ihad expereimented various combination of boundary conditions its either 20% less or 20% more prediction for the values but no where close to the sensible physics. <\/span><\/p>\n

When i set the operating pressure to zero and set gauge pressure to the ambient pressure values which we are usually supposed to do, both hybrid and standard initialization diverge unfortunately. the cfl number is also not too high, I usually run it with 1-2.<\/span><\/p>\n

 <\/p>\n

\"\"<\/span><\/p>\n

I would really need some feasible inputs to go forward. <\/span><\/p>\n","protected":false},"template":"","class_list":["post-356491","topic","type-topic","status-closed","hentry","topic-tag-2d-engine","topic-tag-aerodynamics","topic-tag-ansysfluent","topic-tag-boundary-condition","topic-tag-external-flow","topic-tag-external-flows","topic-tag-fluid-thrust","topic-tag-massflowrate","topic-tag-subsonic-flow-1"],"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\n\t\t\n\t\t\n\t\t