平行レーザビームを用いて傾斜型熱線の傾斜角を測定する方法

A new method was developed for determining an exact slant hot-wire inclination to the axial flow direction in order to accurately measure the transverse velocity component. The method requires dual parallel laser beams near the focal point such as Laser-Two Focus velocimeter beams, one of which can rotate around the other. Since the squared hot-wire bridge output is proportional to the mean value of the beam intensity exposed on the hot-wire element, the bridge output indicates the maximum variation, when the slant wire is exposed to just dual beams. This beam rotating angle is referred to as the slant angle of the wire, if necessary, relative to the freestream angle, which is accurately given by the Laser-Two-Focus velocimeter. Furthermore, it was found in the wire-inclination measurement that the beams rotate in precession due to optical misalignment. This precession is prone to serious errors in this boundary-layer measurements.
資料番号: NALTR1078000
レポート番号: NAL TR-1078