Flow Topology of Gas, Liquid and 3-D Obstacles in Hypersonic Flow

Abstract

The flow topologies of gas and liquid injection into hypersonic crossflow are compared with the flow topology around 3D rigid obstacles in hypersonic flow. Experimental techniques such as oil flow visualization, infrared thermography, sublimation technique and high speed Schlieren photography are applied for a Mach 6 crossing flow on a flat plate. The shock system and the vortex system are visualized and discussed for all cases. Pressure ratio for gas injection, momentum flux ratio for liquid injection and Reynolds number for 3D obstacles are taken into consideration. The effects of non-dimensional numbers on the flow topologies are analyzed. Similarities and differences among different topologies are explained by studying the vortical aerodynamics, making use of CFD simulations.

Experimental Investigation of Liquid Fragmentation In Hypersonic Crossflow

“…One journal paper [16] and three AIAA 1 conference proceedings have been published [10,12,95]. The journal article [16] summarizes the work presented in Chapter 4; whereas the three conference articles summarize the works presented in Chapters 5 [12], 6 [95] and 7 [10] respectively. A comparison of the works presented in Chapters 4 and 7 is also published [9] as a contribution to a book, the Lecture Notes of the Lecture Series organized by the von Karman Institute 2 entitled "Liquid Fragmentation in High Speed Flows" [11].…”

“…Among the 3D roughness elements studied, the cylindrical element possesses very similar flow topology compared to liquid or gas injections. On the other hand, the 3D ramp element has a unique flow topology, where one can observe the lifting off of the initial vortex pair, while generating a counter-rotating vortex pair attached to the surface [12].…”

“…5.1), it is also possible to see the signatures of secondary vortices around this atomization and recirculation zone. Comparing the effect of injector shape, the 1mm diameter circular and streamwise rectangular injectors have very similar flow topologies [12,112].…”

“…3.17), which is not the interesting component for the tested configurations. However, as the main objective is to obtain data on droplet size, it is decided to continue with this setup despite its lack of velocity data [12,94,18].…”

“…The high speed camera is placed above the wind tunnel to detect the signature of the liquid jet illuminated by the laser sheet. A Micro-Nikkor (Nikon) 105mm objective is used at an aperture opening of f1:11 [12].…”