Type of Document Master's Thesis Author Griffith, Dwaine O. URN etd-11212012-040333 Title Turbulence measurements and noise generation in a transonic cryogenic wind tunnel Degree Master of Science Department Mechanical Engineering Advisory Committee
Advisor Name Title Ng, Fai Committee Chair Dancey, Clinton L. Committee Member Moore, John Committee Member Keywords
- Wind tunnels
Date of Defense 1989-04-15 Availability restricted Abstract
A high-frequency combination probe was used to measure dynamic flow quality in the test section of the NASA Langley 0.3-m Transonic Cryogenic Tunnel. The probe measures fluctuating stagnation (total) temperature and pressure, static pressure, and flow angles in two orthogonal planes. Simultaneous unsteady temperature and pressure measurements were also made in the settling chamber of the tunnel. The data show that the stagnation temperature fluctuations remain constant, and the stagnation pressure fluctuations increase by a factor of two, as the flow accelerates from the settling chamber to the test section. In the test section, the maximum rms value of the normalized fluctuating velocity is 0.7 percent. Correlation coefficients l failed to show vortlcity, entropy, or sound as the dominant mode of turbulence in the tunnel.
At certain tunnel operating conditions, periodic disturbances are seen in the data taken in the test section. A possible cause for the disturbances is found to be acoustic coupling of the test section and plenum chamber via the perforated side walls in the tunnel. The experimental data agree well with the acoustic coupling theory.
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