Effect of aspect ratio on the laminar-to-turbulent transition in rectangular channel

The critical Reynolds number of the laminar-to-turbulent transition in the rectangular channel is investigated based on the energy gradient method. The results show that the critical Reynolds number decreases with the increasing aspect ratio. However, the relative location of laminar breakdown does not migrate significantly with the variation of the aspect ratio. In addition, a theoretical correlation as a function of the aspect ratio is proposed to calculate the transition Reynolds number, and the predicted values are in good agreement with the experimental data obtained in the published literatures.

► Effect of aspect ratio on the transition Reynolds number in rectangular channel is studied.
► Prediction correlation for transition Reynolds number is proposed.
► The initiation location of flow transition is studied.