EXPERIMENTAL FLOW CHARACTERIZATION AND HEAT FLUX AUGMENTATION ANALYSIS OF A HYPERSONIC TURBULENT BOUNDARY LAYER ALONG A ROUGH SURFACE D. Neeb, D. Saile, A. Gülhan Supersonic and Hypersonic Technology Department, Institute of Aerodynamics and Flow Technology, DLR Germany 8th European Symposium on Aerothermodynamics for Space Vehicles 2 - 6 March 2015, Lisbon, Portugal
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EXPERIMENTAL FLOW CHARACTERIZATION AND HEAT FLUX AUGMENTATION ANALYSIS OF A
HYPERSONIC TURBULENT BOUNDARY LAYER ALONG A ROUGH SURFACE
D. Neeb, D. Saile, A. GülhanSupersonic and Hypersonic Technology Department, Institute of Aerodynamics and Flow Technology, DLR Germany
8th European Symposium on Aerothermodynamics for Space Vehicles2 - 6 March 2015, Lisbon, Portugal
Surface roughness increases skin friction drag and convective heat transfer above the turbulent level on aircrafts, missiles, re-entry vehicles and propulsion systems
Careful consideration in the prediction of the resulting heat load levels is required for the design of a vehicle
TAU - turb. - Tu nom.TAU - turb. - Tu0.01TAU - turb. - Tu0.02BLcode turb.Run7 iw256x256Run7 iw128x128Run7 iw96x96Run7 iw256x256 to 96x96Run7 iw256x256 to 64x96Run7 iw256x256 to 48x96Run7 iw256x256 to 24x96
Results in increased augmentation with oscillations of higher amplitude and higher mean level of approx. 30%
Peak values are captured by Krogstad model with ks = 0.5 -1.0mm (ks / k = 1 - 2), which is in the same range as compressible literature data and velocity profile prediction
Results in increased augmentation with oscillations of higher amplitude and higher mean level of approx. 30%
Peak values are captured by Krogstad model with ks = 0.5 -1.0mm (ks / k = 1 - 2), which is in the same range as compressible literature data and velocity profile prediction
Zoomed view of the rough surface with increased resolution of ~2pixel per square bar
PIV successfully applied for the first time in the hypersonic regime of H2K
Velocity profiles along smooth cone in good agreement to predictions
Roughness velocity shift clearly detectable and profiles along rough cone
Direct sand grain roughness height extraction via fitting very sensitive and non-unique
higher resolved profiles near the wall with highly stretched interrogation windows will be tested
cumulative rough data analysis of several runs to extract fluctuations for skin friction velocity extraction
2nd profile position data exploitation
Pitot pressure profile measurements
Heat flux augmentation along rough cone sensitive to resolution
With highest possible resolution mean level of augmentation is 30%
higher resolution will be tested to see if result is converged
3D heat flux calculation based on IR data
Both velocity shift and heat flux augmentation are predicted by compressible Krogstadmodel ks = 0.5 -1.0mm (ks / k = 1 - 2), which is in the same range as compressible literature data