Velocity distribution in laminar phases for oscillatory rectangular duct flows with occurrence of turbulent transition
Abstract
Velocity measurements are made for oscillatory air flows in a square duct and a rectangular duct with an aspect ratio of 10. The flow investigated here consists of two phases in each half cycle, namely laminar, or, in a strict sense, quasilaminar phase and turbulent phase. The flow in the latter phase can be considered to be in turbulent quasisteady state. But a flow in laminar phase is quite different from one which is described by the solution for a temporally fully developed oscillatory flow. It is found that the flow reverses its direction at almost the same instant over a whole crosssection, due to a strong mixing of turbulent motion. Taking note of this fact, the flow after reversal may possibly be represented by the case when a fluid suddenly begins laminar motion following prescribed variation of a flow rate. So the analytical solutions are derived for laminar transient flows in a rectangular duct and a parallelplates channel.
 Publication:

JSME International Journal Series B
 Pub Date:
 August 1986
 Bibcode:
 1986JSMEB..29.2447A
 Keywords:

 Computational Fluid Dynamics;
 Ducted Flow;
 Laminar Flow;
 Oscillating Flow;
 Transition Flow;
 Velocity Distribution;
 Air Flow;
 Flow Geometry;
 Velocity Measurement;
 Fluid Mechanics and Heat Transfer