An optical technique for measurement of gas flow profiles utilizing a ring laser.

Fluid flow measurement capabilities of a traveling wave laser oscillator (or ring laser) are assessed theoretically and experimentally. The feasibility of this alternative optical technique for measuring gas flow profiles without insertion of a mechanical probe is examined. Measurements are reported for a range of Reynolds numbers including both laminar and turbulent flows and for a variety of tube diameters. The experimental results are compared with the theory of conditions preceding the establishment of the equilibrium laminar flow profile in round tubes.