Experimental and numerical Investigation of wind tunnel wall interference near Mach one

2001 ◽  
Vol 105 (1052) ◽  
pp. 589-596 ◽  
Author(s):  
M. Mokry ◽  
M. Khalid ◽  
Y. Mébarki ◽  
A. Rebaine
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Numerical Investigation ◽  
Surface Pressure ◽  
Pressure Measurements ◽  
Cfd Simulations ◽  
Tunnel Wall ◽  
Theoretical Analyses

Surface pressure measurements on the CAST-10-2/DOA 2 aerofoil, conducted in the IAR l.5m wind tunnel and supported by CFD simulations, are used to validate some new theoretical analyses of transonic wall interference. Based on the transonic freeze principle, it is shown that the stream Mach number correction is indeterminate near Mach one.

A Comparison Between On-Road and Wind Tunnel Surface Pressure Measurements on a Mid-Sized Hatchback

2007 ◽  
Author(s):  
Andrew A. Lawson ◽  
Robert G. Dominy ◽  
David B. Sims-Williams ◽  
Paul Mears
Keyword(s):  
Wind Tunnel ◽  
Surface Pressure ◽  
Pressure Measurements

scholarly journals Aerodynamics of electric cars in platoon SAGE publications

2020 ◽  
pp. 095440702096502
Author(s):  
Hesham Ebrahim ◽  
Robert Dominy ◽  
Nick Martin
Keyword(s):  
Power Consumption ◽  
Drag Reduction ◽  
Electric Vehicles ◽  
Surface Pressure ◽  
Pressure Field ◽  
Aerodynamic Drag ◽  
Pressure Measurements ◽  
Direct Impact ◽  
Cfd Simulations ◽  
Electric Cars

The potential aerodynamic benefits of operating full-scale electric vehicles in platoons of 2 and 3 vehicles have been investigated. Since drag reduction has a direct impact on vehicle range, power consumption was measured directly and surface pressure measurements were made to characterise the changes in pressure field that influence the power required to overcome aerodynamic drag. CFD simulations were validated against the track measurements to assess the limitations of using a practical, limited number of pressure tappings to measure drag. The overall power consumption for the whole platoon was found to reduce proportionally with the reduction of vehicle spacing and it was also observed that increasing the number of vehicles in the platoon from 2 to 3 further increased the power savings from 33.4% to 39.1%. These power savings were attributed primarily to changes in surface pressure acting on the base of the leading vehicle and the forebody of the trailing vehicle.

scholarly journals High subsonic flow of an organic vapor past a circular cylinder

2021 ◽  
Vol 62 (3) ◽  
Author(s):  
Felix Reinker ◽  
Robert Wagner ◽  
Leander Hake ◽  
Stefan aus der Wiesche
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Wind Tunnel ◽  
Circular Cylinder ◽  
Drag Coefficient ◽  
Surface Pressure ◽  
Subsonic Flow ◽  
Ideal Gas ◽  
Organic Vapor ◽  
Surface Pressure Distribution

AbstractA circular cylinder was tested in the cross-flow of an organic vapor (Novec™ 649) and of air over the subsonic (M < 0.4) and high subsonic (0.4 < M < 0.8) speed range in a continuously running pressurized closed-loop wind tunnel test facility. Time-averaged pressure measurements gave information on surface pressure distributions, and the corresponding drag and base pressure drag coefficients were obtained. Due to the charging of the wind tunnel, different values of the compressibility factor (0.876 < Z < 0.999) could be achieved for the organic vapor flow. This enabled in combination with the results for air an assessment of the impact of non-ideal gas dynamics on the form drag of a cylinder in the considered highly subsonic flow regime. The new experimental data were compared with available literature results. Changes in surface pressure distribution at higher subsonic velocities were identified and discussed. It was found that non-ideal gas effects did not strongly affect the overall drag. The variation of drag coefficient over the Mach number range was comparable with literature data for ideal-gas compressible flow, including shock-less and intermittent shock wave, and permanent shock wave flows regimes. At Mach 0.4, the flow of Novec™ 649 was in the shock-less regime and exhibited a pronounced dependency on the Reynolds number. An increase in drag was observed at Mach 0.6 which was attributed to the commencement of vortex shedding. Non-ideal thermodynamics only affected the flow locally and a reduction of the critical pressure coefficient in the high subsonic flow regime was observed in the surface pressure distribution. However, this mechanism did not alter significantly the overall drag behavior. Graphic abstract Drag coefficient CD against Re for several Mach numbers M and comparison with available literature results obtained for air (colored symbols indicate different Mach number clusters)

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