Two independent versions of the RNG based k ε turbulence model in conjunction with the law of the wall have been applied to the numerical simulation of an axisymmetric turbulent impinging jet flow field. The two m...Two independent versions of the RNG based k ε turbulence model in conjunction with the law of the wall have been applied to the numerical simulation of an axisymmetric turbulent impinging jet flow field. The two model predictions are compared with those of the standard k ε model and with the experimental data measured by LDV (Laser Doppler Velocimetry). It shows that the original version of the RNG k ε model with the choice of C ε1 =1.063 can not yield good results, among them the predicted turbulent kinetic energy profiles in the vicinity of the stagnation region are even worse than those predicted by the standard k ε model. However, the new version of RNG k ε model behaves well. This is mainly due to the corrections to the constants C ε1 and C ε2 along with a modification of the production term to account for non equilibrium strain rates in the flow.展开更多
A theoretical study has been undertaken to determine the flow characteristics associated with a three-dimensional laminar impinging jet issuing from a square pipe nozzle. Interesting flow structures around the jet are...A theoretical study has been undertaken to determine the flow characteristics associated with a three-dimensional laminar impinging jet issuing from a square pipe nozzle. Interesting flow structures around the jet are detected. The numerical result reveals the existence of four streamwise velocity off-center peaks near the impingement plate, which is different from the rectangular jet impingement. The mechanism of the formation of the off-center velocity peaks and the parameters affecting the flow-field characteristics are discussed by comparison of the computed results with different nozzle-to-plate spacings and Reynolds numbers.展开更多
文摘Two independent versions of the RNG based k ε turbulence model in conjunction with the law of the wall have been applied to the numerical simulation of an axisymmetric turbulent impinging jet flow field. The two model predictions are compared with those of the standard k ε model and with the experimental data measured by LDV (Laser Doppler Velocimetry). It shows that the original version of the RNG k ε model with the choice of C ε1 =1.063 can not yield good results, among them the predicted turbulent kinetic energy profiles in the vicinity of the stagnation region are even worse than those predicted by the standard k ε model. However, the new version of RNG k ε model behaves well. This is mainly due to the corrections to the constants C ε1 and C ε2 along with a modification of the production term to account for non equilibrium strain rates in the flow.
文摘A theoretical study has been undertaken to determine the flow characteristics associated with a three-dimensional laminar impinging jet issuing from a square pipe nozzle. Interesting flow structures around the jet are detected. The numerical result reveals the existence of four streamwise velocity off-center peaks near the impingement plate, which is different from the rectangular jet impingement. The mechanism of the formation of the off-center velocity peaks and the parameters affecting the flow-field characteristics are discussed by comparison of the computed results with different nozzle-to-plate spacings and Reynolds numbers.
