Flow field prediction and analysis, project fire final report
Flow field, and convective and radiative heating predictions for NASA Fire project reentry package trajectories
FLOW FIELD↗
SEARCH · Search NASA
Results for “Flow fields”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Space Shuttle Aerothermodynamics Technology Conference. Volume 1: Flow fields
Space shuttle technology conference on flow fields - Vol. 1
Source record↗
Space Station resource node flow field analysis
An analysis of the flow field within the Space Station Freedom resource node with operational intermodule ventilation and temperature/humidity control ventilation systems has been conducted. The INS3D code, an incompressible, steady-state Navier-Stokes solver has been used to assess the design of the ventilation system via quantification of the level of fluid mixing and identification of 'dead air' regions and short-circuit ventilation. Numerical results indicate significant short-circuit ventilation in the forward and midsections of the node and insufficient fluid mixing is found to exist in the aft node section. These results as well as results from a solution grid dependence study are presented.
Kania, Lee↗
Measurements of surface-pressure and wake-flow fluctuations in the flow field of a whitcomb supercritical airfoil
Measurements of surface pressure and wake flow fluctuations were made as part of a transonic wind tunnel investigation into the nature of a supercritical airfoil flow field. Emphasis was on a range of high subsonic Mach numbers and moderate lift coefficients corresponding to the development of drag divergence and buffeting. Fluctuation data were analyzed statistically for intensity, frequency content, and spatial coherence. Variations in these parameters were correlated with changes in the mean airfoil flow field.
Roos, F. W.↗
Euler analysis of the three dimensional flow field of a high-speed propeller: Boundary condition effects
The results of an investigation of the effects of far field boundary conditions on the solution of the three dimensional Euler equations governing the flow field of a high speed single rotation propeller are presented. The results show that the solutions obtained with the nonreflecting boundary conditions are in good agreement with experimental data. The specification of nonreflecting boundary conditions is effective in reducing the dependence of the solution on the location of the far field boundary. Details of the flow field within the blade passage and the tip vortex are presented. The dependence of the computed power coefficient on the blade passage and the tip vortex are presented. The dependence of the computed power coefficient on the blade setting angle is examined.
Nallasamy, M.↗
Euler analysis of the three-dimensional flow field of a high-speed propeller - Boundary condition effects
The results of an investigation of the effects of far field boundary conditions on the solution of the three dimensional Euler equations governing the flow field of a high speed single rotation propeller are presented. The results show that the solutions obtained with the nonreflecting boundary conditions are in good agreement with experimental data. The specification of nonreflecting boundary conditions is effective in reducing the dependence of the solution on the location of the far field boundary. Details of the flow field within the blade passage and the tip vortex are presented. The dependence of the computed power coefficient on the blade passage and the tip vortex are presented. The dependence of the computed power coefficient on the blade setting angle is examined.
Nallasamy, M.↗
Experimental investigation of a simulated LOX injector flow field
Current development of liquid oxidizer injectors for liquid rocket engines is highly dependent upon experimental investigations of the two-phase liquid oxidizer/gaseous fuel injection plume characteristics. This paper describes an effort to increase the applicability of optical diagnostic approaches to such flow fields find includes an innovative approach for interpreting laser-induced fluorescence signals from axisymmetric two-phase flows. The usefulness of both laser-induced fluorescence and surface scattering techniques are explored herein. The flow field selected for this investigation is an oxidizer-swirled, coaxial flow produced using an injector design under consideration for use in the Space Transportation Main Engine (STME). The liquid oxygen (LOX) flow through this injector is simulated using water. Photographs of laser-induced fluorescence and particle scattering and measured profiles of the mass distribution in this flow field are presented and discussed herein.
Hartfield, Roy J., Jr.↗
Prediction of fluctuating pressure environments associated with plume-induced separated flow fields
The separated flow environment induced by underexpanded rocket plumes during boost phase of rocket vehicles has been investigated. A simple semi-empirical model for predicting the extent of separation was developed. This model offers considerable computational economy as compared to other schemes reported in the literature, and has been shown to be in good agreement with limited flight data. The unsteady pressure field in plume-induced separated regions was investigated. It was found that fluctuations differed from those for a rigid flare only at low frequencies. The major difference between plume-induced separation and flare-induced separation was shown to be an increase in shock oscillation distance for the plume case. The prediction schemes were applied to PRR shuttle launch configuration. It was found that fluctuating pressures from plume-induced separation are not as severe as for other fluctuating environments at the critical flight condition of maximum dynamic pressure.
Plotkin, K. J.↗
Calculation of downstream radiative flow fields with massive ablation
Progress in developing rigorous flow field models for downstream radiative flows of massive ablation is reported. It is indicated that the biggest unknown is the turbulent model for the mixing layer and that there is a need for approximate solutions.
Walberg, G.↗
Injection and distribution of liquids in the flow fields of blunt shapes at hypersonic speeds
A possible method for reducing the attenuation of radio transmission from hypersonic vehicles is by injection of a liquid into the flow field. The hot plasma layer surrounding the vehicle could presumably be quenched if the latent heat of the liquid and the heat capacity of the vapor could be utilized efficiently. In the case of stagnation-point injection, the momentum of the liquid could be utilized to modify the bow shock and possibly reduce the initial ionization. To attain these objectives of efficient coolant utilization or modification of the bow shock a knowledge of the liquid injection, atomization, spray penetration, and evaporation processes is required. This report presents the results of a study of liquid injection into hypersonic flow fields. A simplified theory for evaporation distances is derived and is shown to be in qualitative agreement with experimental data. Correlation of experimental data for maximum cross-current penetration of the liquid spray for injection near the shoulder pf a hemisphere cylinder, a sphere 9° cone, and a Mercury model are given. These data were obtained in the Langley Mach 8 variable density tunnel with both liquid nitrogen and water injection to provide a large range of liquid parameters. Flow-field disturbances, as indicated by schlieren photographs and surface pressures, increased with the ratio of coolant mass flux to airstream mass flux. For stagnation-point injection, the maximum shock standoff distance was correlated by the ratio of the liquid jet momentum flux to the airstream momentum flux.
Ivan E. Beckwith↗
Numerical flow field prediction for Project RAM-C
Shock layer flow field calculations for RAM-C PROJECT
FLOW FIELD↗
Numerical study of scramjet and ramjet flow fields
Two computer programs have been developed to numerically calculate complex, two-dimensional flow fields in scramjets. The first program is written for inlet analysis whereas the second program is written primarily for combustor analysis. Both programs solve the full two-dimensional Navier-Stokes equations by a well-known explicit, predictor-corrector technique. Turbulence is modeled by an algebraic eddy-viscosity model. The combustor program also includes one or more species conservation equations to calculate mixing and reacting flows. The hydrogen/air chemistry in this program is modeled by a complete reaction model. The combustor program has been recently modified to analyze axisymmetric ramjet dump combustor flow field. Results from these computer programs are presented that predict the flow in several scramjet inlet configurations, two model scramjet engine configurations, and in a dump combustor simulator. Computed results are also compared with available experimental data to allow assessment of the programs.
Kumar, A.↗
Prediction of the flow-field interference induced by the long-range laser velocimeter in the Ames 40- by 80-foot and the 80- by 120-foot wind tunnels
The predicted flow disturbances induced in the test sections of the Ames 40- by 80-Foot Wind Tunnels by the presence of the Long-Range Laser Velocimeter (LRLV) are presented. The predictions were made using a potential-flow paneling code to model the test section and the LRLV, and a calculation of the resulting flow field was made. The flow velocity and angularity were calculated at numerous locations in the flow field relative to the LRLV, and the results are presented.
Reinath, M. S.↗
Numerical simulation of three-dimensional supersonic inlet flow fields
Supersonic inlet flows with mixed external-internal compressions of an axisymmetric inlet model were computed using a combined implicit-explicit (Beam-Warming-Steger/MacCormack) method for solving the three-dimensional unsteady, compressible Navier-Stokes equations in conservation form. Numerical calculations were made of various flows typically found in supersonic inlets such as shock-wave intersections, flow spillage around the cowl lip, shock-wave/boundary-layer interactions, control of shock-induced flow separation by means of boundary layer bleed, internal normal (terminal) shocks, and the effects of flow incidence. Computed results were compared with available wind tunnel data.
Kawamura, T.↗
Reattachment studies of an oscillating airfoil dynamic stall flow field
The reattaching flow over an oscillating airfoil executing large amplitude sinusoidal motion around a mean angle of attack of 10 degrees has been studied using the techniques of stroboscopic schlieren, two component laser Doppler velocimetry and point diffraction interferometry, for a free stream Mach number of 0.3 and a reduced frequency of 0.05. The results show that the dynamically stalled flow reattaches in a process that begins when the airfoil is very close to the static stall angle on its downward stroke and progresses over the airfoil through a large range of angles of attack as the airfoil decreases to about 6 degrees. The airfoil suction peak shows a dramatic rise as the static stall angle is approached and the velocity profiles develop such that the flow near the surface is accelerated. The process completes through the disappearance of a separation bubble that forms over the airfoil.
Ahmed, S.↗
Measurement and prediction of propeller flow field on the PTA aircraft at speeds of up to Mach 0.85
High speed subsonic transports powered by advanced propellers provide significant fuel savings compared to turbofan powered transports. Unfortunately, however, propfans must operate in aircraft-induced nonuniform flow fields which can lead to high blade cyclic stresses, vibration and noise. To optimize the design and installation of these advanced propellers, therefore, detailed knowledge of the complex flow field is required. As part of the NASA Propfan Test Assessment (PTA) program, a 1/9 scale semispan model of the Gulfstream II propfan test-bed aircraft was tested in the NASA-Lewis 8 x 6 supersonic wind tunnel to obtain propeller flow field data. Detailed radial and azimuthal surveys were made to obtain the total pressure in the flow and the three components of velocity. Data was acquired for Mach numbers ranging from 0.6 to 0.85. Analytical predictions were also made using a subsonic panel method, QUADPAN. Comparison of wind-tunnel measurements and analytical predictions show good agreement throughout the Mach range.
Aljabri, Abdullah S.↗
Predictions and implications of the flow field parameter analysis of the wind induced oscillation problem
Flow field analysis of wind induced oscillation in stationary launch vehicles
LAUNCH VEHICLE↗
The vortex interaction in a propeller/stator flow field
The vortex interaction encounered in the flow field of a propeller and a stator has been investigated using smoke flow visualization. A stator at angle of attack was used to generate a line vortex which interacted with the helical vortex filaments generated by a propeller. Changes in the relative vortex strengths and vortex rotational directions yielded several distinct vortex structures. Axial flow in the vortex cores is determined to influence the development of the vortex interaction.
Johnston, R. T.↗