China
Africa
Explore chapters and articles related to this topic
Rail Vehicle Aerodynamics
Published in Simon Iwnicki, Maksym Spiryagin, Colin Cole, Tim McSweeney, Handbook of Railway Vehicle Dynamics, 2019
Typically, wind tunnels are classified by the range of flow speed or its Mach (Ma) number in the test section, including low-speed wind tunnel (Ma < 0.3), subsonic wind tunnel (0.3 ≤ Ma < 0.8), transonic wind tunnel (0.8 ≤ Ma < 1.4), supersonic wind tunnel (1.4 ≤ Ma < 5) and hypersonic wind tunnel (Ma > 5). For rail vehicles, the low-speed and subsonic wind tunnels are appropriate if Ma < 0.5. Two types of wind tunnels are used for rail vehicles: open-circuit wind tunnel (Figure 12.3) and closed-circuit wind tunnel (Figure 12.4). To reduce ground effects, the wind tunnel for rail vehicle tests should be equipped with a special ground device, using a conveying belt or ground with suction system.
Numerical study of discrete film cooling near the rudder shaft of a hypersonic air fin model
Published in Numerical Heat Transfer, Part A: Applications, 2023
Siming Dai, Haiteng Ma, Ziran Xu, Kangjun Feng
Experimental baseline comes from Zhang et al. [11], which was conducted in a hypersonic wind tunnel with a low noise at National University of Defense Technology. As shown in the experimental setup of Figure 3, compressed air storage and vacuum tank provide a large pressure difference, generating a high-speed freestream, which is heated before entering the setting chamber. After being accelerated by the nozzle designed for Ma = 6, mainstream moves into the test section and is dumped by the vacuum tank. Nano-based planar laser scattering (NPLS) [53] is used for flow visualization. Temperature sensitive paints (TSP) is selected to measure the heat transfer on the surface of the air fin and flat plate. According to the flow visualization result of Zhang et al. [11], flow near the air fin is either transitional or turbulent, although the incoming freestream is laminar. Therefore, Reynolds Averaged Navier-Stokes (RANS) model is selected to resolve turbulent stresses in numerical simulations.
Simulation of the effects of dilution gas for the formation of CJ plane during the oblique detonation
Published in Numerical Heat Transfer, Part A: Applications, 2023
Zhang et al. [27] reported the results of the first experiments conducted in a hypersonic wind tunnel in 2022 with a large-scale hydrogen-powered oblique detonation engine model. The Chapman–Jouguet detonation was partially achieved under all conditions considered with curved wavefronts. Stronger concentration gradients, however, induced several critical structures, including local quenching and a Straw-Hat structure [28].