Issue 10 Volume 41 May 16, 2003

profile. Results from channel-flow simulation indicate that in order to obtain the correct mean velocity profile (the log law),
the wall stresses must not only model the physics but also compensate for numerical and SGS modeling errors. The data
generated by this sub-optimal control strategy are then used to derive a linear stochastic estimate model. The mathematical
formulation and issues of key importance in control-based wall modeling are detailed. Efforts towards a predictive and
inexpensive wall model in the control framework are detailed.
DTIC
Large Eddy Simulation; Mathematical Models; Stochastic Processes; Wall Flow; Fluid Mechanics
20030034665 National Taiwan Univ., Taipei, Taiwan, Province of China
Implementation of Noninvasive Flow Velocimetry Through Monte Carlo Simulation
Chien, Jen-Chien; Lin, Bor-Shyh; Lin, Bor-Shing; Wu, Shu-Mei; Chong, Fok-Ching; October 25, 2001; 4 pp.; In English;
Original contains color illustrations
Report No.(s): AD-A410380; No Copyright; Avail: CASI; A01, Hardcopy
One of the most important mechanisms for maintaining the life of human beings is the human circulation system. This
research focuses on a noninvasive technique that maintains high resolution and high precision of measuring photon in the
blood stream. We hope to obtain important biomedical parameters valuable for pathological diagnosis. In phase I, a
noninvasive optical flow velocimetry is implemented for detecting the human circulation system under the skin surface. The
sonrce of the incidence photon is He-Ne laser. The signal is transmitted and detected via a Y-type optical fiber. Optical
heterodyning is used to measure the frequency difference between the reflection wave and the original incidence laser wave.
Then numerical simulation using Monte Carlo was used in the analysis to verify the result. In phase II, after a velocimetry
specification was decided, it was modeled, tested and verified using Monte Carlo simulation. Then the apparatus were set up
as directed in the model. The performance of this velocimetry is satisfaction and acceptable. This method of implementing a
velocimetry is simple, convenience and fast. Thus, no prior clinical experiment is needed. Moreover, the best reading for the
reflected wave is 45 degrees plus/minus 2.35 degrees. This is a realtime and continuous detecting blood flow velocimetry. We
find that this is a reliable tool for doctors when doing clinical diagnosis.
DTIC
Blood Flow; Particle Image Velocimetry; Helium-Neon Lasers
20030034671 Air Force Research Lab., Edwards AFB, CA, USA
Fractal Geometry and Growth Rate Changes of Cryogenic Jets Near the Critical Point
Chehroudi, B.; Talley, D.; Coy, E.; June 14, 1999; 16 pp.; In English
Contract(s)/Grant(s): AF Proj. 2308
Report No.(s): AD-A410388; AFRL-PR-ED-TP-FY99-0146; No Copyright; Avail: CASI; A03, Hardcopy
Injection of several pure fluids into a chamber with different ambient gases under supercritical temperature but sub- to
supercritical condition based on the injectant thermodynamic critical conditions resulted in the following: the jet exhibits
classical liquid-like jet second wind-induced type breakup until chamber pressure reaches near the critical point of the jet
substance beyond which gas-like visual behavior is observed and no drops are found. For the first time, these visual qualitative
observations are verified quantitatively by agreement between the experimental growth rate of the jets reported here and those
developed theoretically by D. Brown, D. Papamoschou and A. and Roshko, and P.E. Dimotakis for the incompressible
variable-density mixing layers. This gas-like jet appearance is also confirmed quantitatively and for the first time by fractal
analysis of the outer contour of the jet. The geometry of the jet interface shows a transition from Euclidean to a fractal interface
with a fractal dimension near the values measured and reported by others for gaseous turbulent jets. Finally, based on a
physical hypothesis implying that at the point where gas-like behavior appears, the value of the jet interface bulge
separation/formation characteristic time should be near that of gasification, an ‘intuitive/smart’ equation is proposed for the
growth rate that agrees well with the presented experimental data for a wide range of density ratios.
DTIC
Fractals; Turbulent Flow; Supercritical Flow; Liquid Rocket Propellants; Fluid Jets; Cryogenic Rocket Propellants
20030034675 Air Force Research Lab., Edwards AFB, CA, USA
Anatomical Changes of a Cryogenic Jet in Transition to the Thermodynamic Supercritical Condition
Chehroudi, B.; Talley, D.; Coy, E.; May 1999; 8 pp.; In English
Contract(s)/Grant(s): Proj-2308
Report No.(s): AD-A410389; AFRL-PR-ED-TP-FY99-0089; No Copyright; Avail: CASI; A02, Hardcopy
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