1992 年 12 巻 1Supplement 号 p. 87-90
A two-channel LDV system is used to carry out the air flow measurements around passenger car models in a scale wind tunnel. A 2-watt argon-ion laser is used as the light source. The main optical unit and the probe head are connected by optical fiber cables. The probe head consists of a compact LDV probe, a beam expander and a focusing lens, which has a long focal length and can he traversed easily. A new type signal processor, incorporating a digital auto-correlation scheme, is employed to process the Doppler signals. Mean air flow velocities and turbulence intensities are calculated by a microcomputer. The flow measurements on the wake of car models were performed by this system. The results of the experiments show that reverse flow takes place just behind car bodies, and can clarify the difference in the flow field between the cases with and without a rear spoiler. It has been pointed out from the results that the present LDV system provides accurate flow measurements around passenger car models in scale wind tunnel tests.