Technical Paper
The Effect of Gravity Induced Buoyancy on Velocity Measurement in 1-g Environment
2001-07-09
2001-01-2256
The effects of testing cabin ventilation in gravity to meet a requirement for ventilation on orbit were analyzed. Buoyancy is due to the combined presence of a density gradient within the fluid and a body force that is proportional to the fluid density. Since gravity cannot be removed, the test must be conducted with air at as near to constant density as practical in order to remove buoyancy effects. The effects of gravity induced buoyancy force on the velocity field was analyzed by the Richardson number. Computational Fluid Dynamics (CFD) analysis was performed to verify the theoretical methods. The velocity data for a 1-g and a no gravity case were compared. The ratio between local velocity and free stream velocity, u/U∞ were analyzed for the dimensionless parameter, η (= y ✓ U∞/νx). There is a relatively sharp rise in the profile near the wall and an overshoot of the velocity beyond its free stream value.