Comments by students on Environmental Engineering Seminar held during spring 1970

August 1970.CER70-71HR10

Diffusion and decay of turbulent elliptic wakes

CER65YHK-LVB42.CEP66-67LVB-YHK68.August 1965.Includes bibliographical references (page 13).Research Sponsored by the Bureau of Ships Fundamental Hydromechanics Research Program. Administered by the NONR 1610(08).Three-dimensional, turbulent wakes having elliptical cross-sections were studied both experimentally and analytically for a constant-fluid-property, zero-pressure-gradient flow. An analytical solution for wake diffusion and decay was obtained from a linearized momentum equation by assuming a constant eddy viscosity in the transverse plane but variable along the wake centerline. The experimental data confirmed the prediction that elliptical wakes approach a axisymmetry far downstream. Data were obtained in wakes of 1 inch and 3 inch diameter disks having eccentricities of 1.0, 0.6 and 0.2 over a mean Reynolds number range from 2.4 x 10^4 to 7.1 x 10^4 Mean velocity and turbulent intensity data were gathered between 8 and 266 diameters downstream of the disks. Several arbitrary constants of the analysis were determined so that engineering estimates can be made from the analytical results. Unlike axisymmetric and two-dimensional geometries, elliptic wakes offer an opportunity to test eddy viscosity assumptions in one plane without adjustable factors, and this was done. However, the mean velocity profiles deviated from the predicted Gaussian shape even though approximate similarity was attained far downstream

Test of Phillips' hypothesis for eddy viscosity in pipe flow, A

CER67-68LVB-RDH46.February 1968.Paper submitted to A.I.Ch.E. journal.Includes bibliographical references

Aerodynamic Mixing Downstream from Line Source of Heat in High-intensity Sound Field

Theory and measurement showed that the heat wake downstream from a line source is displaced by a transverse standing sound wave in a manner similar to a flag waving in a harmonic mode. With a 147 db, 104 cps standing wave, time-mean temperatures were reduced by an order of magnitude except near the displacement-pattern nodal points. The theory showed that a 161 db, 520 cps standing wave considerably increased the mixing in both the time-mean and instantaneous senses

Preliminary survey of propulsion using chemical energy stored in the upper atmosphere

Ram-jet cycles that use the chemical energy of dissociated oxygen for propulsion in the ionosphere are presented. After a review of the properties and compositions of the upper atmosphere, the external drag, recombination kinetics, and aerodynamic-heating problems of an orbiting ram jet are analyzed. The study indicates that the recombination ram jet might be useful for sustaining a satellite at an altitude of about 60 miles. Atmospheric composition and recombination-rate coefficients were too uncertain for more definite conclusions. The ram jet is a marginal device even in the optimistic view

Innovative, off-campus educational programs of Colorado State University

CER71-72LVB43.April, 1972.Includes bibliographical references (pages 33-34).Special Report to the President's Science Advisory Committee, Panel on Educational Research and Development

Fundamental study of a submerged and non-submerged three dimensional jet impinging upon a normal plane

CER63GLS1.Includes bibliographical references.Final report to National Science Foundation.Part I, Axisymmetric boundary-layer of a jet impinging on a smooth plate: The flow characteristics of a radial wall jet formed by the normal impingement of an air jet on a smooth fiat plate have been studied. The mean velocity and the turbulence statistics for different orifice velocities and diameters were measured with a pitot tube and a hot-wire anemometer. Most of the measurements were made at ten vertical stations spaced at 6 in. intervals along a radius. The first station was twelve inches from the stagnation point. A particular form for the turbulent shear stress is proposed. Using the incompressible boundary-layer approximations and a similarity assumption, the momentum and continuity equations were used to derive expressions in the form of a n exponential decay for the peak radial velocity and a linear growth for the boundary layer thickness with respect to the radial distance from the center. The measured profiles of velocity and turbulent intensities were found to be approximately similar; thus, approximate universal functions were obtained by expressing U/(U sub m) ,√(U12)(U sub m), √(V12)/(U sub m) and √(W12)/(U sub m) (the relative velocity and turbulent intensities respectively) in terms of a non-dimensional vertical coordinate L = ʓ/(δ sub 0.5). The characteristic length (δ sub 0.5) was chosen as the height where U/(U sub m) = 0.5. The mean velocity profile of the inner boundary-layer does not follow the pipe wall law and only a limited region can be approximated by the logarithmic form. This is attributed to the effects of the highly turbulent flow within the outer layer of the wall jet which produces disturbances penetrating deeply into the inner boundary-layer. Consequently, a higher wall shear stress results in this wall jet flow than in ordinary two- dimensional boundary-layer flow. The wall s hear stress was found to be approximately proportional to the invers e square of the radial distance.Under grant NSF G-9434.Part I. Ph.D. Dissertation: Axisymmetric boundary-layer of a jet impinging on a smooth plate by Yeong-ging Tsuei -- Part II. Appendix A: An analysis of the momentum equation for the turbulent wall jet by Junn-Ling Chao and Lionel V. Baldwin

NACA Technical Notes

Report presenting over 1000 measured convective heat-transfer coefficients for normal cylinders in subsonic slip flow that have been correlated by using Nusselt number as a function of Reynolds and Knudsen (or Mach) numbers. A complicated nonlinear dependence of the heat-transfer coefficient to the difference between cylinder and recovery temperature is reported. The application of these results to hot-wire anemometry is also discussed

Evaluation of dominant variables in design of evaporator bodies

CER62LVB-SSK60.October 1962.Prepared for Stearns-Roger Manufacturing Company, Denver, Colorado.Series statement on title page: CER62LVB-SSK60.Includes bibliographical references