2019 Volume 14 Issue 1 Pages JFST0006
In this study, we compare the flow and temperature fields of a heated impinging jet interfering with a Couette flow and a Poiseuille flow through numerical simulations. We find that the instantaneous vortex structure in the Couette main flow has some periodicity and affects the heat transfer on the jet impinging surface. In time-averaged flow and temperature fields, the Nusselt number shows unique distributions. Further, a counter-rotating vortex pair is extracted, similar to the previously reported studies on a jet in a cross flow. It is found that this vortex pair involves the main flow fluid and causes a unique Nusselt number distribution. The overall heat transfer in the Couette main flow is lower than that in the Poiseuille main flow. From the mean velocity field, a back current occurs behind the jet inlet, which is similar to the separation in the wake flow of a cylinder crossing the main flow. In addition, the fluctuation velocity in the Couette main flow does not spread wider than that in the Poiseuille main flow, and high velocity fluctuations concentrate on the front edge of the jet flow. The distributions of both mean and fluctuation velocities of the Couette flow interfering with the jet are similar to those of the turbulent Couette flow.
