Application of the Laser Velocimeter for Trailing Vortex Measurements

Abstract : This report summarizes a three-year analytical and experimental program to develop a dual-scatter laser velocimeter system to map the flow fields of trailing vortices stemming from the wingtips of flying aircraft. The basic design parameters ascertaining feasibility of the LV-measuring technique are presented. Included is a discussion and evaluation of a newly developed two-dimensional Bragg cell (TDBC) for resolving directional ambiguity. The electronics instrumentation developed for the operation of the TDBC is evaluated in detail. In addition, the development of a direct readout system yielding considerable improvement over the initial instrument is described and evaluated.

[1]  W M Farmer,et al.  Measurement of particle size, number density, and velocity using a laser interferometer. , 1972, Applied optics.

[2]  F. L. Crosswy,et al.  Signal-Conditioning Electronics for a Vector Velocity Laser Velocimeter. , 1973 .

[3]  W. H. Stevenson,et al.  Optical frequency shifting by means of a rotating diffraction grating. , 1970, Applied optics.

[4]  W. Yanta,et al.  The Use of a Laser Doppler Velocimeter in Supersonic Flow , 1971 .

[5]  J. A. L. Thomson,et al.  Laser-Doppler system for detection of aircraft trailing vortices , 1970 .

[6]  Irene A. Stegun,et al.  Handbook of Mathematical Functions. , 1966 .

[7]  Laser Doppler velocity measurement without directional ambiguity by using frequency shifted incident beams , 1970 .

[8]  E. H. Linfoot.  Principles of Optics , 1961 .

[9]  D. L. Fried,et al.  Optical heterodyne detection of an atmospherically distorted signal wave front , 1967 .

[10]  J. C. Owens.  Optical doppler measurement of microscale wind velocity , 1969 .

[11]  K. Bullrich,et al.  Scattered Radiation in the Atmosphere and the Natural Aerosol , 1964 .

[12]  W. Mcgowan.  Remote detection of turbulence in clear air. , 1971 .

[13]  Jumes F. Meyers.  Investigation and calculations of basic parameters for the application of the laser Doppler velocimeter , 1971 .

[14]  H. Hodara,et al.  Laser wave propagation through the atmosphere , 1966 .

[15]  R. A. Silverman,et al.  Wave Propagation in a Turbulent Medium , 1961 .

[16]  Clarke E. Harris,et al.  Remote detection of trailing vortices, task 3, modification 3 , 1971 .

[17]  K L Orloff,et al.  Two-color dual-beam backscatter laser Doppler velocimeter. , 1973, Applied optics.

[18]  J. Milgram,et al.  Optical Detection of Local Fluid-Flow Velocities by Filtering in Space and Time , 1967 .

[19]  F L Crosswy,et al.  Two-component dual-scatter laser Doppler velocimeter with frequency burst signal readout. , 1973, Applied optics.

[20]  W. H. Stevenson,et al.  Oscillatory Flow Measurements with a Directionally Sensitive Laser Velocimeter , 1970 .

[21]  W M Farmer,et al.  Determination of a third orthogonal velocity component using two rotationally displaced laser Doppler velocimeter systems. , 1972, Applied optics.

[22]  A. E. Lennert,et al.  Development of a Laser Velocimeter to be Used in AEDC Wind Tunnels. , 1970 .

[23]  R. G. Joppa.  A method of calculating wind tunnel interference factors for tunnels of arbitrary cross-section , 1967 .

[24]  G. W. Willard.  Criteria for Normal and Abnormal Ultrasonic Light Diffraction Effects , 1949 .

[25]  M J Rudd,et al.  A new theoretical model for the laser Dopplermeter , 1969 .

[26]  Y. Yeh,et al.  Observation of Diffusion Broadening of Rayleigh Scattered Light , 1964 .

[27]  J. D. Fridman,et al.  Laser Doppler instrumentation for the measurement of turbulence in gas and fluid flows , 1970 .