Laminarturbulent transition and velocity profiles of oscillatory rectangular duct flows
Abstract
Oscillatory air flows in ducts of rectangular cross section with aspect ratios 1, 5 and 10 are investigated experimentally. On the basis of the inspections of hotwire signals, flow types can be classified into laminar, transitional, and turbulent regimes; and these regimes are well delimitated using two parameters defined in terms of hydraulic diameter, crosssectional mean velocity amplitude, kinematic viscosity, and angular frequency. For fully developed steady turbulent flows in a square and a twodimensional duct, the approximate solutions for the axial mean velocity profiles are derived on the assumption of eddyviscosity distributions. In the phase when turbulent bursts occur, instantaneous velocity profiles of measured oscillatory duct flows are well described by these solutions.
 Publication:

JSME International Journal Series B
 Pub Date:
 July 1984
 Bibcode:
 1984JSMEB..27.1399O
 Keywords:

 Ducted Flow;
 Flow Velocity;
 Oscillating Flow;
 Transition Flow;
 Unsteady Flow;
 Air Flow;
 Eddy Viscosity;
 Laminar Flow;
 Turbulent Flow;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer