Scientific and Technical Aerospace Reports Volume 39 April 6, 2001

20010024042 Houston Univ., Dept. of Mechanical Engineering, TX USA
A Robust Scheme for Control of Skin Friction and Heat Transfer in Turbulent Boundary Layers via a New Instability
Mechanism Final Report, 1 Jan. 1998-31 Mar. 2000
Hussain, Fazle, Houston Univ., USA; Nov. 03, 2000; 22p; In English
Contract(s)/Grant(s): F49620-98-1-0150
Report No.(s): AD-A384670; AFRL-SR-BL-TR-00-0627; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
Using direct numerical simulations of turbulent channel flow, we present new insight into the generation of streamwise vortices
near the wall, and an associated drag reduction strategy. Growth of x-dependent spanwise velocity disturbances w(x) is shown
to occur via two mechanisms: (i) linear transient growth, which dominates early-time evolution, and (ii) linear normal-mode instability,
dominant asymptotically at late time (for frozen base flow streaks). Approximately 25% of streaks extracted from near-wall
turbulence are shown to be strong enough for linear instability (above a critical vortex line Lift angle). However, due to viscous
annihilation of streak normal vorticity COy, normal mode growth ceases after a factor of two energy growth. In contrast, the linear
transient disturbance produces a 20-fold amplification, due to its rapid, early-time growth before significant viscous streak decay.
Thus, linear transient growth of w(x) is revealed as a new, apparently dominant, generation mechanism of x-dependent turbulent
energy near the wall.
DTIC
Turbulent Boundary Layer; Vortices; Drag Reduction; Turbulent Flow; Turbulent Heat Transfer; Boundary Layer Control
20010024883 NASA Langley Research Center, Hampton, VA USA
An Experimental and CFD Study of a Supersonic Coaxial Jet
Cutler, A. D., George Washington Univ., USA; White, J. A., NASA Langley Research Center, USA; [2001]; 12p; In English; 39th;
Aerospace Sciences, 8-11 Jan. 2001, Reno, NV, USA; Sponsored by American Inst. of Aeronautics and Astronautics, USA
Contract(s)/Grant(s): NCC1-370
Report No.(s): AIAA Paper 2001-0143; Copyright Waived; Avail: CASI; A03, Hardcopy; A01, Microfiche
A supersonic coaxial jet facility is designed and experimental data are acquired suitable for the validation of CFD codes
employed in the analysis of high-speed air-breathing engines. The center jet is of a light gas, the coflow jet is of air, and the mixing
layer between them is compressible. The jet flow field is characterized using schlieren imaging, surveys with pitot, total temperature
and gas sampling probes, and RELIEF velocimetry. VULCAN, a structured grid CFD code, is used to solve for the nozzle
and jet flow, and the results are compared to the experiment for several variations of the kappa - omega turbulence model
Author
Computational Fluid Dynamics; Structured Grids (Mathematics); Supersonic Jet Flow; K-Omega Turbulence Model
20010024890 NASA Glenn Research Center, Cleveland, OH USA
Proceedings of the Fifth Microgravity Fluid Physics and Transport Phenomena Conference
Singh, Bhim S., Editor, NASA Glenn Research Center, USA; Proceedings of the Fifth Microgravity Fluid Physics and Transport
Phenomena Conference; December 2000; 2002p; In English; 5th; Fifth Microgravity Fluid Physics and Transport Phenomena
Conference, 9-11 August 2000, Cleveland, OH, USA; See also 20010024891 through 20010025024
Contract(s)/Grant(s): RTOP 101-43-0B
Report No.(s): NASA/CP-2000-210470; E-12466; NAS 1.55:210470; No Copyright; Avail: CASI; A99, Hardcopy; A10, Microfiche
The Fifth Microgravity Fluid Physics and Transport Phenomena Conference provided the scientific community the opportunity
to view the current scope of the Microgravity Fluid Physics and Transport Phenomena Program and research opportunities
and plans for the near future. Consistent with the conference theme ”Microgravity Research an Agency-Wide Asset” the conference
focused not only on fundamental research but also on applications of this knowledge towards enabling future space exploration
missions. The conference included 14 invited plenary talks, 61 technical paper presentations, 61 poster presentations, exhibits
and a forum on emerging research themes focusing on nanotechnology and biofluid mechanics. This web-based proceeding
includes the presentation and poster charts provided by the presenters of technical papers and posters that were scanned at the
conference site. Abstracts of all the papers and posters are included and linked to the presentations charts. The invited and plenary
speakers were not required to provide their charts and are generally not available for scanning and hence not posted. The conference
program is also included.
Author
Conferences; Microgravity; Gravitational Effects; Fluid Dynamics; Heat Transfer
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