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A theoretical study was conducted to determine the effects of adverse pressure gradient and compressibility in modeling turbulent compressible flows. The zero equation, kinetic-energy/dissipation eddy-viscosity models, and Reynolds stress model predictions are presented and compared with experimental data. It is shown that the effects of compressibility, which include the mass-averaged fluctuation term u j '', the pressure-dilatation term p'∂u l ''/∂x l , and the dilatation dissipation μ(∂u l ''/∂x l ) 2 /p, are important in modeling turbulent compressible flows

In this paper we describe the hypervelocity facilities and instrumentation for the aerothermal and aero-optical studies of hypersonic interceptors. We first review the major fluid dynamic phenomena that control the flowfield environment around an interceptor. The key role of duplicating flowfield velocity for the simulation of both fluid dynamic and real-gas effects is discussed. The design and operating characteristics of the Large Energy National Shock tunnel (LENS) facility is then described, and the test conditions that will be obtained for endointerceptor studies are discussed. The surface and flowfield instrumentation that will be used to determine the aerothermal characteristics of the flowfield over the hypersonic vehicle is described. Finally we discuss the aero-optic instrumentation which is used to evaluate the optical degradation through the shock layer surrounding the vehicle.

The creation of an overseas mental health crisis intervention team is described. The authors discuss the unique aspects of an overseas low intensity conflict environment and the importance of immediate mental health responses to disaster situations in such theaters. Key elements in the formation of the team are the use of local resources, command endorsement, and an emphasis on education of commanders and team members. Examples are cited of other military response team deployments. The authors present their experience in Panama as a model for other providers in similar environments.

In the preceding article, the authors described the formation of an overseas mental health crisis intervention team. In this paper, the application of the United States Southern Command Crisis Intervention Team in the aftermath of a recent tragedy in Panama is described. A chronology of the disaster, involving two helicopter crashes which left 11 dead, is presented. The intervention that followed is described in detail. The emphasis is on four main areas: education, identification, process, and follow-up. The authors present their experience in an effort to provide an intervention strategy for other isolated mental health providers.

A program of experimental research and analysis was conducted to examine the heat transfer and pressure distributions in regions of shock/shock interaction over smooth and transpiration-cooled hemispherical noseshapes. The objective of this investigation was to determine whether the large heat transfer generated in regions of shock/shock interaction can be reduced by transpiration cooling. The experimental program was conducted at Mach numbers of 12 to 16 in the Calspan 48-Inch Shock Tunnel. Type 3 and type 4 interaction regions were generated for a range of freestream unit Reynolds numbers to provide shear layer Reynolds numbers from 10 exp 4 to 10 exp 6 to enable laminar and turbulent interaction regions to be studied. Shock/shock interactions were investigated on a smooth hemispherical nosetip and a similar transpiration-cooled nosetip, with the latter configuration being examined for a range of surface blowing rates up to one-third of the freestream mass flux. While the heat transfer measurements on the smooth hemisphere without shock/shock interaction were in good agreement with Fay-Riddell predictions, those on the transpiration-cooled nosetip indicated that its intrinsic roughness caused heating-enhancement factors of over 1.5. In the shock/shock interaction studies on the smooth nosetip, detailed heat transfer and pressure measurements were obtained to map the variation of the distributions with shock-impingement position for a range of type 3 and type 4 interactions. Such sets of measurements were obtained for a range of unit Reynolds numbers and Mach numbers to obtain both laminar and turbulent interactions. The measurements indicated that shear layer transition has a significant influence on the heating rates for the type 4 interaction as well as the anticipated large effects on type 3 interaction heating. In the absence of blowing, the peak heating in the type 3 and type 4 interaction regions, over the transpiration-cooled model, did not appear to be influenced by the model's rough surface characteristics. The studies of the effects of the transpiration cooling on type 3 and type 4 shock/shock interaction regions demonstrated that large surface blowing rates had significant effect on the structure of the flowfield, enlarging the shock layer and moving the region of peak-heating interaction around the body.

A theoretical study was conducted to determine the effects of adverse pressure gradient and compressibility in modeling turbulent compressible flows. The kinetic energy/dissipation and Reynolds stress model predictions are presented and compared with experimental data. The effects of compressibility, which include the mass averaged fluctuation term, the pressure dilatation term, and the dilatation dissipation, are important in modeling the turbulent compressible flows. The normal stresses and longitudinal strain rates also have an effect in the prediction of turbulent energy productions on the curved surfaces. A new compressible formulation of the pressure strain term, which includes the dilatation effects, in the Reynolds stress equation is presented.

Facility requirements for hypersonic propulsion system testing and the capabilities or limitations of selected hypersonic testing facilities are briefly reviewed. The specific advantages and limitations of the shock tunnel for hypersonic propl.;1.sion testing are discussed, and areas are identified where shock-tunnel research can supplement other ground tests and flight experiments in the development of air-breathing propulsion at hypersonic speeds. Other chapters in this volume will describe several other relevant facilities in detail, so the discussion in this chapter will be limited to a response to many of the perceived limitations associated with the short-duration approach to obtaining fundamental data applicable to high-enthalpy environments. Shock-tunnel testing of both scramjet combustor and exhaust nozzle configurations at conditions corresponding to flight at Mach numbers of 10-12 at altitudes of 100,000 ft and above are considered. Sample computations are presented to demonstrate that real-gas effects, and in particular, the departure from vibrational and chemical equilibrium in the facility nozzle expansion do not significantly impact the ability to simulate the desired test flows. Rather, it is the facility limitations in producing the flow enthalpies and test time that impact the simulation of flight conditions for NASP-like configurations.

A review is presented of some important aerothermal problems associated with hypersonic flight with emphasis on those involved with viscous/inviscid interaction. The flow regimes of importance to hypersonic vehicles of current interest are discussed and the performance of experimental facilities currently available to study real gas phenomena associated with hypervelocity flight are briefly reviewed. Viscous interaction and real gas effects in hypervelocity flight at high altitudes are discussed with reference to measurements which are required to support the development of improved prediction capabilities in this regime. Theoretical and experimental research on 2D and 3D shock wave/laminar boundary layer interaction relevant to the performance of control surfaces and inlets in hypersonic flight at high altitudes is reviewed. The characteristics of transition regions in hypersonic flows are discussed with particular reference to transitional flows over nosetips and swept leading edges. Studies of shock interaction phenomena on indented nosetips are discussed, followed by a review of the surface roughness and blowing effects. Research to describe the characteristics of 2D and 3D regions of shock wave/turbulent boundary layer interaction in hypersonic flow is reviewed with particular reference to intrinsic unsteadiness and potential compressibility effects in these flows. This review is concluded with a brief discussion of observations suggesting a decrease in the spreading rate in shear layer mixing in hypersonic flow.