Heat transfer and pressure distributions on spherically blunted 25 deg half-angle cone at Mach 8 and angles of attack up to 90 deg
Hypersonic heat transfer and pressure distribution on spherically blunted cone
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Hypersonic heat transfer and pressure distribution on spherically blunted cone
A major challenge in understanding differences in electric propulsion performance in ground tests and in space operations concerns the pressure distribution within the test vacuum chamber. The chamber backpressure is much higher than experienced in space, modifying thruster performance and plume dynamics. Numerical simulation is a key element to determining the background conditions in non-ideal vacuum chamber environments. An important parameter for the accurate simulation of chamber backpressure is the probability that an atom will stick to a cryogenic panel used to pump away the plume gases. This quantity can be used to model vacuum pumps in particle-based kinetic numerical methods. In this work, a three-dimensional direct simulation Monte Carlo code is used to model neutral xenon atoms flowing from the anode of the H9 Hall Effect Thruster within the University of Michigan’s Large Vacuum Test Facility. Simulated pressures are compared with ion gauge pressure measurements to infer the effective sticking coefficient of the chamber’s vacuum pumps. A pressure predicting surrogate model is developed for inference of pump sticking coefficients and for uncertainty quantification. This information enables accurate and useful kinetic simulations of electric propulsion thruster plasma plumes in vacuum chambers.
Results from pressure distribution tests on 0.04-scale and 0.02-scale models of the forward fuselage of the Space Shuttle Orbiter are presented without analysis. The tests wre completed in the Langley Continuous Flow Hypersonic Tunnel (CFHT). The 0.04-scale model was tested at angles of attack from -5 deg to 45 deg and angles of sideslip from -3 deg to 3 deg. The 0.02-scale model was tested at angles of attack from -10 deg to 45 deg and angles of sideslip from -5 deg to 5 deg. The tests were conducted in support of the development of the Shuttle Entry Air Data System (SEADS). In addition to modeling the 20 SEADS pressure orifices, the wind-tunnel models were also instrumented with orifices to match Development Flight Instrumentation (DFI) port locations currently existing on the Space Shuttle Orbiter Columbia (OV-102). This DFI simulation has provided a means for comparisons between reentry flight pressure data and wind-tunnel data.
Wind tunnel investigation of static pressure distributions along cylindrical surface behind shallow, three dimensional, rearward facing step of various heights
A major source of the noise generated by high bypass ratio aircraft fan engines is the unsteady pressures (forces and moments) acting on the fan blades. These unsteady pressures are the result of the interaction of the blades with the wakes of upstream blade rows, inlet flow distortions, and inlet turbulence. An experimental system was developed which will permit the measurement of the unsteady pressure distributions; a series of experiments were conducted to investigate these effects, and the results are compared with predictions from existing theoretical analyses.
An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to measure static pressure distributions inside a nonaxisymmetric thrust reversing nozzle. The tests were made at nozzle total pressures ranging from ambient to about eight times ambient pressure at a free stream Mach number of zero. Tabulated pressure data are presented.
At the request of the Army Air Corps, an investigation of the pressure distribution over PW-9 wing models was conducted in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics. The primary purpose of these tests was to obtain wind-tunnel data on the load distribution on the cellule to be correlated with similar information obtained in flight tests, both to be used for design purposes. Because of the importance of the conditions beyond the stall as affecting the control and stability, this investigation was extended through 90 degree angle of attack. The results for the range of normal flight have been given in NACA Technical Report No. 271. The present paper presents the same results in a different form and includes, in addition, those over the greater range of angle of attack, -18 degrees through 90 degrees. The results show that: (1) at angles of attack above maximum lift, the biplane upper wing pressures are decreased by the shielding action of the lower wing. (2) the burble of the biplane lower wing, with respect to the angle of attack, is delayed, due to the shielding action of the lower wing. (3) the center of pressure of the biplane upper wing (semispan) is, in general, displaced forward and outward with reference to that of the wing as a monoplane, while for the lower wing there is but slight difference for both conditions. (4) the overhanging portion of the upper wing is little affected by the presence of the lower wing.
Pressure distributions and aerodynamic characteristics of Nimbus B fuel capsule in hypersonic flow
The results of pressure distribution tests conducted in the Langley Unitary Plan wind tunnel are presented. The data were obtained for three sets of cruciform aft-tail control surfaces on a wingless missile model at Mach numbers of 1.60, 2.36, and 3.70 for angles of attack from -4 degrees to 20 degrees, model roll angles from 0 degrees to 90 degrees, and tail deflections of 0 degrees and 15 degrees. The test Reynolds number used was 6.6 million per meter.
The results of pressure distribution tests are presented without analysis. The test Reynolds number used was 6.6. x 10 to the 6th power per meter.
The results of pressure distribution tests conducted in a wind tunnel are presented without analysis. The data were obtained for trapezoidal aft tail control surfaces on a wingless missile model at Mach numbers of 1.60, 2.36, and 3.70 for angles of attack from -4 to 20 deg model roll angles from 0 to 90 deg and tail deflections of 0 and -15 deg. The test Reynolds number used was 6.6 million per meter.
Force measurements and pressure distribution measurements on the midsection were made on a rectangular wing with slotted droop nose and end plates, on which could be placed a choice of either a plain flap-split flap combination or a slotted flap. (author)
Results from pressure distribution tests on 0.04-scale and 0.02-scale models of the forward fuselage of the Space Shuttle Orbier are presented without analysis. The tests were completed in the Langley 20-Inch Mach 6 Tunnel. The 0.04-scale model was tested at angles of attack from 0 to 35 and angles of sideslip from 0 to -4. The 0.02-scale model was tested at angles of attack from -10 to 45 and angles of sideslip from 0 to -4. The tests were conducted in support of the development of the Shuttle Entry Air Data System (SEADS). In addition to modeling the 20 SEADS pressure orifices, the wind-tunnel to models were also instrumented with orifices to match Development Flight Instrumentation (DFI) port locations currently existing on the Space Shuttle Orbiter Columbia (OV-102). This DFI simulation had provided a means for comparisons between reentry flight pressure data and wind-tunnel data.
Surface pressure distribution on spherical blunted cones, and correlation of Mach numbers, cone angle, and angle of attack
Wind tunnel tests to determine flow patterns and pressure distributions around bluff afterbody in wake of 120 deg cone for various separation distances at Mach 3.0
Report presents the results of pressure-distribution measurements on a 1/40-scale model of the U. S. Airship "Akron" conducted in the NACA 20-foot wind tunnel. The measurements were made on the starboard fin of each of four sets of horizontal tail surfaces, all of approximately the same area but differing in span-chord ratio, for five angles of pitch varying from 11.6 degrees to 34 degrees, for four elevator angles, and at air speeds ranging from 56 to 77 miles per hour. Pressures were also measured at 13 stations along the rear half of the port side of the hull at one elevator setting for the same five angles of pitch and at an air speed of approximately 91 miles per hour. The normal force on the fin and the moment of forces about the fin root were determined. The results indicate that, ignoring the effect on drag, it would be advantageous from structural considerations to use a fin of lower span-chord ratio than that used on the "Akron."
A subcritical panel method applied to flow analysis and aerodynamic design of complex aircraft configurations is presented. The analysis method is based on linearized, compressible, subsonic flow equations and indirect Dirichlet boundary conditions. Quadratic dipol and linear source distribution on flat panels are applied. In the case of aerodynamic design, the geometry which minimizes differences between design and actual pressure distribution is found iteratively, using numerical optimization technique. Geometry modifications are modeled by surface transpiration concept. Constraints in respect to resulting geometry can be specified. A number of complex 3-dimensional design examples are presented. The software is adopted to personal computers, and as result an unexpected low cost of computations is obtained.
In an attempt to follow the time rate of change of the processes in turbulent flows by quantitative measurements the measurement of the pressure is often beset with insuperable difficulties for the reason that the speeds and hence the pressures to be measured are often very small. On the other hand, the measurement of very small pressures requires, at least, considerable time, so that the follow-up of periodically varying processes is as goad as impossible. In order to obviate these difficulties a method, suggested by Prof. Prandtl, has been developed by which the pressure distribution is simply determined from the photographic flow picture. This method is described and proved on a worked-out example. It was found that quantitatively very satisfactory results can be achieved.