Aerodynamic and noise simulation of compressible supersonic gas flow exiting from tube

Simulation of supersonic compressible gas flow has been investigated while exiting from 7.62 mm diameter tube in the axis-symmetric geometry. Density-based solver and adaptive dynamic mesh methods were applied based on static pressure gradient. Simulations have been carried out using inviscid and k-ɛ turbulence models. Time of first, second, and main flow shock waves and their progress were also investigated. Existing experimental Schlieren shadowgraphs were compared with density contours of simulations and static pressure results within the shock waves were also compared with the results of literature and good agreements have been achieved. After verification, simulation results have been applied in order to extract sound pressure level values using Ffowcs-Williams and Hawkins (FWH) model. Sound pressure receivers have been located in1, 2,6,10 and 15 m far from the sound source and sound pressure levels have been obtained and compared at the three different times. Results were in good agreement with test data of existing literature. Maximum sound pressure level was obtained in the time of 0.58 millisecond equaling 119 dB. Simulations results showed that changing viscous model from inviscid to k-ɛ turbulence model had an insignificant effect on the noise values.