A mathematical model for investigating the stability of thermally stratified flow of unbounded viscous incompressible fluid
Mathematical models for investigating stability of thermally stratified shear flow in atmosphere
Gage, K. S.↗
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Heat flow and thermal history of the moon
An analysis was made of current heat flow data and thermal models of lunar evolution which satisfy the diverse information that has accumulated on internal processes.
Lyubimova, Y. A.↗
Choking of a subsonic gas flow by thermal radiation.
Thermal radiation effects on subsonic flow of ideal gray gas, calculating streamwise variations of flow properties
George, Y. H.↗
Turbulence and surface heat transfer near the stagnation point of a circular cylinder in turbulent flow
A turbulent boundary layer flow analysis of the momentum and thermal flow fields near the forward stagnation point due to a circular cylinder in turbulent cross flow is presented. Turbulence modeling length scale, anisotropic turbulence initial profiles and boundary conditions were identified as functions of the cross flow turbulence intensity and the boundary layer flow far field velocity. These parameters were used in a numerical computational procedure to calculate the mean velocity, mean temperature, and turbulence double correlation profiles within the flow field. The effects of the cross flow turbulence on the stagnation region momentum and thermal flow fields were investigated. This analysis predicted the existing measurements of the stagnation region mean velocity and surface heat transfer rate with cross flow Reynolds number and turbulence intensity less than 250,000 and 0.05, respectively.
Wang, C. R.↗
Thermally conductive flows in coronal holes
A treatment of polytropic solar wind flows in non-radial expansion regions, developed by Kopp and Holzer (1976), is extended to include the effect of thermal conduction. Thermal conductive and polytropic flows in the lower corona under specified high-speed stream conditions at 1 AU are compared; the thermally conductive flows more closely model the observed phenomena, though predicted electron density is still too low and the predicted temperature too high. It is suggested that another mechanism (such as wave pressure), in conjunction with thermal conduction, may provide an accurate explanation for solar wind flows originating in coronal holes.
Steinolfson, R. S.↗
The effect of power law body forces on a thermally-driven flow between concentric rotating spheres
A numerical study is conducted to determine the effect of power-law body forces on a thermally-driven axisymmetric flow field confined between concentric co-rotating spheres. This study is motivated by Spacelab geophysical fluid-flow experiments, which use an electrostatic force on a dielectric fluid to simulate gravity; this force exhibits a (1/r)sup 5 distribution. Meridional velocity is found to increase when the electrostatic body force is imposed, relative to when the body force is uniform. Correlation among flow fields with uniform, inverse-square, and inverse-quintic force fields is obtained using a modified Grashof number.
Macaraeg, M. G.↗
The effect of power-law body forces on a thermally driven flow between concentric rotating spheres
A numerical study is conducted to determine the effect of power-law body forces on a thermally-driven axisymmetric flow field confined between concentric co-rotating spheres. This study is motivated by Spacelab geophysical fluid-flow experiments, which use an electrostatic force on a dielectric fluid to simulate gravity; this force exhibits a (1/r)sup 5 distribution. Meridional velocity is found to increase when the electrostatic body force is imposed, relative to when the body force is uniform. Correlation among flow fields with uniform, inverse-square, and inverse-quintic force fields is obtained using a modified Grashof number.
Macaraeg, M. G.↗
Heat flow and thermal processes in the Jornada delMuerto, New Mexico
Most heat flow data in rifts are uncertain largely because of hydrologic disturbances in regions of extensive fracturing. Estimates of heat flow in deep petroleum tests within a large basin of the Rio Grande rift, which has suffered little syn-rift fracturing, may begin to provide clearer insight into the relationships between high heat flow and crustal thinning processes. The Jornada del Muerto is a large basin located in the Rio Grande rift of south central New Mexico. The region of interest within the Jornada del Muerto is centered about 30 km east of the town of Truth or Consequences, and is approximately 60 km north-south by 30 km east-west. High heat flows are estimated for the region. Values increase from about 90 mWm(-2) in the northern part of the study area to about 125 mWm(-2) in the southern part. These high heat flows are rather enigmatic because in the immediate vicinities of the sites there is little evidence of Cenozoic volcanism or syn-rift extensional tectonics. It is suggested that the geothermal anomaly in the southern Jornada del Muerto (approx. 125 to approx. 95 mWm(-2) results from some type of mass movement-heat transfer mechanism operating in the crust just below the elastic layer. This conclusion is consistent with the geologic and geophysical data which describe a thin crust, apparently devoid of features indicative of extensional-tectonics in the upper part of the lastic crust.
Reiter, M.↗
Upper ocean thermal and flow fields at 0 deg, 28 deg W (Atlantic) and 0 deg, 140 deg W (Pacific) during 1983-1985
Moored current and temperature measurements were recorded simultaneously for 2 years (August 1983 to July 1985) at six or seven depths between 10 and 250 m on the equator at 28 deg W in the Atlantic and at 140 deg W in the Pacific. The mean depth of the 20-C isotherm, which was representative of thermocline displacements, was identical at both sites. Substantially different annual cycles of the thermal and flow fields represent an enigma. The annual variation of the 20-C isotherm was much less at 140 deg W than at 28 deg W.
Halpern, David↗
Crystallization, flow and thermal histories of lunar and terrestrial compositions
Contents: a kinetic treatment of glass formation; effects of nucleating heterogeneities on glass formation; glass formation under continuous cooling conditions; crystallization statistics; kinetics of crystal nucleation; diffusion controlled crystal growth; crystallization of lunar compositions; crystallization between solidus and liquidus; crystallization on reheating a glass; temperature distributions during crystallization; crystallization of anorthite and anorthite-albite compositions; effect of oxidation state on viscosity; diffusive creep and viscous flow; high temperature flow behavior of glass-forming liquids, a free volume interpretation; viscous flow behavior of lunar compositions; thermal history of orange soil material; breccias formation by viscous sintering; viscous sintering; thermal histories of breccias; solute partitioning and thermal history of lunar rocks; heat flow in impact melts; and thermal histories of olivines.
Uhlmann, D. R.↗
Collimation of high-speed flow with thermal spread losses
The operation of the neutral beam collimator designed for the mass spectrometer inlet system of the Space Shuttle Induced Environment Contamination Monitor system is discussed. The collimator will allow selective views of a 10 deg half-angle conical volume of space so that backscattered molecules from within this volume can be measured and related to the column densities of outgassing species. Gas molecules which enter the collimator but do not have a view from the entrance orifice to the exit are directed to a gas getter and eliminated. The loss of properly directed molecules in the collimator due to their thermal distribution is calculated for the case of a directed flow, which would occur when the collimator is pointed in the direction of motion of the spacecraft. Inlet to outlet flux ratios are also computed as a function of angle of attack.
Taeusch, D. R.↗
Viscous stability theory for thermally stratified flow - Discontinuous jets and shear layers.
The method used by Drazin to investigate the stability of unbounded, viscous, homogeneous, parallel shear flow to small wavenumber disturbances is extended to study the effect of thermal stratification on the stability of unbounded jets and shear layers. By this method the stability characteristics of continuous profiles are inferred from the stability characteristics of discontinuous profiles. The characteristic value problem for discontinuous jet and shear layers is posed by the requirement that the solutions of the governing differential equation satisfy the matching conditions and boundedness conditions for layers that extend to infinity. The analysis leads to a characteristic determinant which is required to vanish for the characteristic values of the parameters: the Reynolds number, the wavenumber, and the wave speed. The stabilizing effect of the thermal stratification as parameterized by the Richardson number was found to be most stabilizing for small wavenumber (large-scale) disturbances.
Gage, K. S.↗
Thermal and heat flow instrumentation for the space shuttle Thermal Protection System
The 100 mission lifetime requirement for the space shuttle orbiter vehicle dictates a unique set of requirements for the Thermal Protection System (TPS) thermal and heat flow instrumentation. This paper describes the design and development of such instrumentation with emphasis on assessment of the accuracy of the measurements when the instrumentation is an integral part of the TPS. The temperature and heat flow sensors considered for this application are described and the optimum choices discussed. Installation techniques are explored and the resulting impact on the system error defined.
Hartman, G. J.↗
Direct simulation of AFE forebody and wake flow with thermal radiation
Calculated results for the flowfield structure and surface quantities are presented for an axisymmetric representation of an aeroassist flight experiment vehicle. The direct simulation Monte Carlo (DSMC) method is used to perform the calculations, since the flow is highly nonequilibrium about the vehicle during both the compression and expansion phases. The body configuration is an elliptically blunt nose followed by a skirt with a circular radius and an afterbody. Freestream conditions correspond to a single point along the entry trajectory at an altitude of 90 km and a velocity of 9.9 km/s. The calculations account for nonequilibrium in the translational and internal modes, dissociation, ionization, and thermal radiation. The degree of dissociation is large, but the maximum ionization is only about 2 percent by mole fraction. The bluntforebody flow experiences a high degree of thermal nonequilibrium in which the translational temperature is generally greater than the internal temperature. However, as the flow expands about the aerobrake skirt and afterbody, the internal temperature is generally greater than the translational temperature.
Moss, James N.↗
Direct simulation of AFE forebody and wake flow with thermal radiation
Calculated results for the flowfield structure and surface quantities are presented for an axisymmetric representation of an aeroassist flight experiment vehicle. The direct simulation Monte Carlo (DSMC) method is used to perform the calculations, since the flow is highly nonequilibrium about the vehicle during both the compression and expansion phases. The body configuration is an elliptically blunt nose followed by a skirt with a circular radius and an afterbody. Freestream conditions correspond to a single point along the entry trajectory at an altitude of 90 km and a velocity of 9.9 km/s. The calculations account for nonequilibrium in the translational and internal modes, dissociation, ionization, and thermal radiation. The degree of dissociation is large, but the maximum ionization is only about 2 percent by mole fraction. The blunt forebody flow experiences a high degree of thermal nonequilibrium in which the translational temperature is generally greater than the internal temperature. However, as the flow expands about the aerobrake skirt and afterbody, the internal temperature is generally greater than the translational temperature.
Moss, James N.↗
Approximate Turbulent Boundary-Layer Development in Plane Compressible Flow Along Thermally Insulated Surfaces with Application to Supersonic-Tunnel Contour Correction
Numerical solutions of the differential equation obtained from the momentum theorem for the development of a turbulent boundary layer along a thermally insulated surface in two-dimensional and in radial shock-free flow are presented in tabular form for a range of Mach numbers from 0.100 to 10. The solution can be used in a step-wise procedure with any given distribution of favorable pressure gradients and for zero pressure gradients. Solutions are also given for use with moderate adverse pressure gradients. The mean velocity in the boundary layer is approximated by a power-law profile. In view of the stepwise integration methods to be used, the exponent designated the profile shape can be varied along the surface between the integral fraction limits 1/5 and 1/11 through interpolation. Agreement obtained between theoretical and experimental boundary-layer development in a supersonic nozzle at a nominal Mach number of 2 indicates the general validity of the approximations used in the analysis - in particular, the method of extrapolating low-speed skin-friction relations to high Mach number flows. The extrapolation method used assumes that the skin-friction coefficient depend primarily on Reynolds number, provided that the density and the kinematic viscosity are evaluated at surface conditions.
BOUNDARY LAYER - WIND TUNNEL WALLS↗
Development of prediction techniques for multi-jet thermal ground flow fields and fountain formation
Avoiding detrimental ground interaction is important for practical V/STOL aircraft. This paper reports recent developments in a numerical method for estimating thermal ground footprints. Upwash and fountain formation for arbitrarily oriented jet arrangements is predicted. Flow asymmetry due to roll, pitch, differential thrust or ground inclination is included. The prediction methodology uses simple inviscid relations for energy and momentum conservation along with an empirical entrainment law, applied in independent sectors of the wall jet and upwash. Asymmetrical stagnation line prediction is compared with experiment. Detailed flow measurements for a three-jet interaction are also presented.
Siclari, M. J.↗
Surface brightness temperatures at the Apollo 17 heat flow site - Thermal conductivity of the upper 15 cm of regolith
Lunar surface brightness temperatures derived as part of the Apollo 17 heat flow experiment are reported. Nighttime surface temperatures, calculated from the data provided by two thermocouples suspended about 15 cm above the lunar surface, are used to determine the conductivity profile of the upper 15 cm of regolith at the ALSEP site. The surface reaches a maximum temperature of 384 (plus or minus 6) K at lunar noon and cools to a minimum temperature of 102 (plus or minus 1.5 K) at the end of the lunar night. Conductivities of the order of .000015 W/cm-deg K are postulated for a 2-cm porous surface layer overlying more compact regolith material with conductivities in the range of .0001 to .00015 W/cm-deg K between 2 and 15 cm. A mean surface temperature of 216 (plus or minus 5) K is deduced from the thermocouple data. The 256 K temperature measured by the probe sensors at 130 cm thus indicates that a large mean temperature gradient exists at the Apollo 17 site.
Keihm, S. J.↗