An evaluation of factors affecting the flow quality in wind tunnels
Abstract
Tests were conducted in a number of NASA wind tunnels to measure disturbance levels and spectra in their respective settling chambers, test sections, and diffusers to determine the sources of these disturbances. Results indicate that properly designed and located second minimum in transonic tunnels prevent fluctuation originating at struts and in diffusers from propagating upstream into the test section. The installation in or upstream of the settling chamber of carefully selected screens, honeycomb, and acoustic baffles could further reduce test section turbulence levels and scales without significant pressure losses. The performance of these modifications is strongly influenced by tunnel geometry and their influence on the mean flow around the circuit.
- Publication:
-
In AGARD Wind Tunnels and Testing Tech. 22 p (SEE N84-23564 14-01
- Pub Date:
- February 1984
- Bibcode:
- 1984wttt.agar.....O
- Keywords:
-
- Flow Characteristics;
- Pressure Oscillations;
- Turbulence;
- Wind Tunnels;
- Baffles;
- Energy Spectra;
- Flow Measurement;
- Flow Velocity;
- Honeycomb Structures;
- Temperature Distribution;
- Velocity Distribution;
- Fluid Mechanics and Heat Transfer