Topic
Freestream
About: Freestream is a research topic. Over the lifetime, 3428 publications have been published within this topic receiving 56147 citations.
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TL;DR: An experimental investigation of sonic air, CO2 and Helium transverse jets in Mach 5 cross flow was carried out over a flat plate, and the penetration patterns were found to be remarkably different both at the nearfield and the farfield.
Abstract: An experimental investigation of sonic air, CO2 and Helium transverse jets in Mach 5 cross flow was carried out over a flat plate. The jet to freestream momentum flux ratio, J, was kept the same for all gases. The unsteady flow topology was examined using high speed schlieren visualisation and PIV. Schlieren visualisation provided information regarding oscillating jet shear layer structures and bow shock, Mach disc and barrel shocks. Two-component PIV measurements at the centreline, provided information regarding jet penetration trajectories. Barrel shocks and Mach disc forming the jet boundary were visualised/quantified also jet penetration boundaries were determined. Even though J is kept the same for all gases, the penetration patterns were found to be remarkably different both at the nearfield and the farfield. Air and CO2 jet resulted similar nearfield and farfield penetration pattern whereas Helium jet spread minimal in the nearfield.
27 citations
TL;DR: In this article, the corrected section drag coefficient and effective drag coefficient were calculated for the half-chord chord of the airfoil chord of a single chord in a single-antenna chord.
Abstract: Nomenclature c — airfoil chord cd = corrected section drag coefficient cdg = effective drag coefficient rake = d drag coefficient from wake survey ct = section lift coefficient cm = pitching moment about the half-chord C^ = blowing momentum coefficient, =m-Vj/(qco'S) h = slot height m =jet mass flow A^ = freestream Mach number qx = freestream dynamic pressure s = chordwise slot location S =wing reference area V = velocity a. = angle of attack
27 citations
TL;DR: In this article, a nonoverlapping multidomain spectral collocation method was developed to solve compressible viscous flows over a flat plate, where the advection terms were treated with a characteristic correction method.
27 citations
TL;DR: In this article, the authors indicate some general correlations of the available wake-transition data for spheres, cones, wedges, cylinders, and sphere-cones with the free-stream Reynolds number and the freestream Mach number.
Abstract: Introduction T purpose of the present note is to indicate some general correlations of the available wake-transition data for spheres, cones, wedges, cylinders, and sphere-cones" ; the parameters used are the freestream Reynolds number (based on the transition length measured from the base of the body) and the freestream Mach number Additionally, it is found that, by multiplying the Reynolds number by a suitable Mach number function, the effects of body shape are scaled out (within the inherent scatter), and the data for all body shapes correlate This Mach number function is the square of the ratio of freestream Mach number to local inviscid Mach number in the wake region
26 citations
TL;DR: In this paper, hydrogen, helium, and nitrogen were injected from a converging slot nozzle perpendicular to the heated Mach 2.5 airstream above a flat plate, and the dependence of the separation distance, wall pressure, and side force on the jet to freestream pressure and density ratios and the separation Reynolds number was determined.
Abstract: Pressure, temperature, gas sampling, and optical measurements were made in the turbulent separated flow region upstream of jets. Hot hydrogen, helium, and nitrogen were injected from a converging slot nozzle perpendicular to the heated Mach 2.5 airstream above a flat plate. The dependence of the separation distance, wall pressure, and side force on the jet to freestream pressure and density ratios and the separation Reynolds number was determined. The injectant concentration in the separated flow region was found to be high, and to correlate with a ratio of the injectant and freestream temperatures and molecular weights. A tracer gas injection technique was used to determine air and injectant mass transport rates through the separated flow region. Approximately five percent of the gas injected passed through this region.
26 citations