The computation of complex jet and nozzle flows
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Barton, J. M.↗
Engineering topics
Birch, S. F.
Publications and source records attributed to Birch, S. F..
Turbulence models from the point of view of an industrial user
Since there appears to be little prospect of the development of methods for the solution of the full, time dependent Navier-Stokes equations in the near future, the need continues for turbulence models to approximate the Reynolds stress terms that appear in the time averaged Navier-Stokes equations. Even if methods were available for solving the full equations, this would not necessarily be the optimum choice in all cases. As the cost of numerical computations decreases, the trend toward the use of more complex methods is likely to continue, but there will always be a need for a range of methods, depending on the accuracy and detail required from the calculation.
Birch, S. F.↗
Mean flow field and surface heating produced by unequal shock interactions at hypersonic speeds
Mean velocity profiles were measured in a free shear layer produced by the interaction of two unequal strength shock waves at hypersonic free-stream Mach numbers. Measurements were made over a unit Reynolds number range of 3,770,000 per meter to 17,400,000 per meter based on the flow on the high velocity side of the shear layer. The variation in measured spreading parameters with Mach number for the fully developed flows is consistent with the trend of the available zero velocity ratio data when the Mach numbers for the data given in this study are taken to be characteristic Mach numbers based on the velocity difference across the mixing layer. Surface measurements in the shear-layer attachment region of the blunt-body model indicate peak local heating and static pressure consistent with other published data. Transition Reynolds numbers were found to be significantly lower than those found in previous data.
Birch, S. F.↗
Mean flow development and surface heating for an attaching compressible free shear layer
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Rudy, D. H.↗
Free turbulent shear flows. Volume 2: Summary of data
The proceedings of a conference on free turbulent shear flows are presented. Objectives of the conference are as follows: (1) collect and process data for a variety of free mixing problems, (2) assess present theoretical capability for predicting mean velocity, concentration, and temperature distributions in free turbulent flows, (3) identify and recommend experimental studies to advance knowledge of free shear flows, and (4) increase understanding of basic turbulent mixing process for application to free shear flows. Examples of specific cases of jet flow are included.
Birch, S. F.↗
A critical review of the experimental data for developed free turbulent shear layers
Experimental shear layer data are reviewed and the results are compared to numerical predictions for three test cases. It was concluded from the study that many, if not most, of the apparent inconsistencies which exist in the interpretation of the experimental data for free shear layers result from confusing data taken in developed turbulent flows with those taken in transitional or developing flows. Other conclusions drawn from the study include the following: (1) The effects of Mach number are more uncertain primarily because of limited data and the absence of any turbulence measurements for supersonic shear layers. (2) The data available for heterogeneous shear layers are not sufficient to clearly establish the effect of density ratio on mixing rate.
Birch, S. F.↗
Mean flow and turbulence measurements in a Mach 5 shear layer.
Hot-wire study of turbulent mixing in the near field of a Mach 5 jet with extension of the results into the hypersonic range. Mean and fluctuating measurement data are given for the free shear layer of the 10.6-cm diameter jet which was contained in a 61-by-61 cm vacuum chamber and exhausted into a diffuser 44 cm downstream of the jet exit. An auxiliary air supply was used to equalize the static pressures in the chamber and the nozzle. The nozzle wall boundary layer was turbulent at the jet exit, providing measurement data at higher Reynolds numbers, which are also included.
Morrisette, E. L.↗
Transition in compressible free shear layers.
The transition Reynolds number for shear layers produced by interactions between weak and strong shock waves is determined on the basis of experiments performed in a 20-in. (Mach 6) and an 11-in. (Mach 6.9) hypersonic tunnel. A variable angle wedge was used to generate a planar shock wave which interacted with the bow wave of a blunt body. An average value of the transition length (defined as the length along the shear layer from the shock interaction to the point where turbulence became visible on schlieren photographs) was used to determine the transition Reynolds number.
Birch, S. F.↗