DEVELOPMENT AND TESTS OF AN AIR-JET OIL BOOM1

1979 ◽  
Vol 1979 (1) ◽  
pp. 483-487 ◽  
Author(s):  
Steven H. Cohen ◽  
William T. Lindenmuth ◽  
John S. Farlow
Keyword(s):  
Structural Design ◽  
Water Surface ◽  
Surface Current ◽  
High Volume ◽  
Turbulent Shear ◽  
Operational Feature ◽  
Turbulent Shear Stress ◽  
Air Jet ◽  
Environmental Test ◽  
Jet Nozzle

ABSTRACT This paper describes the development of the Air-Jet Boom—a novel boom which has the capability to divert oil slicks under wave and current conditions that normally preclude the deployment of conventional booms. Tests at the EPA's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) facility have demonstrated that this boom can, for example, successfully divert oil slicks at 3 knots with 85 percent efficiency when at 30° to the flow. Moreover, with the addition of steep, 4-foot waves, the boom's performance is virtually unchanged. 1 The key operational feature is a continuous, horizontally-oriented air jet ejected from along the boom near the water surface. The flow interaction and the ensuing momentum transfer from the air jet to the water surface (by viscous and turbulent shear stress) induces a strong local surface current just ahead of the boom. When the boom is deployed at an angle to the flow (diversionary mode), the induced current causes the oncoming oil slick to be deflected and transported across the water surf ace, apart from the clean underlying flow. Overall, each boom module is about 33 feet long and 2 feet in diameter. Major components include two inflatable sections (ducts) supporting the continuous air-jet nozzle and a center support-float/jet-pump arrangement to supply the high volume, low-pressure (23,000 SCFM at 3 inches of water) air flow required for operation. Some unique features of the structural design are low draft (one inch) and excellent compliance to waves. Furthermore, the sections are lightweight and highly compactible for storage.

Flow structure of the free round turbulent jet in the initial region

1979 ◽  
Vol 90 (3) ◽  
pp. 531-539 ◽  
Author(s):  
L. Bogusławski ◽  
Cz. O. Popiel
Keyword(s):  
Kinetic Energy ◽  
Turbulent Shear ◽  
Axial Distance ◽  
Initial Region ◽  
Mean Velocity ◽  
The Core ◽  
Turbulent Shear Stress ◽  
Air Jet ◽  
The Mean ◽  
Good Agreement

This note presents measurements of radial and axial distributions of mean velocity, turbulent intensities and kinetic energy as well as radial distributions of the turbulent shear stress in the initial region of a turbulent air jet issuing from a long round pipe into still air. The pipe flow is transformed relatively smoothly into a jet flow. In the core subregion the mean centre-line velocity decreases slightly. The highest turbulence occurs at an axial distance of about 6d and radius of (0·7 to 0·8)d. On the axis the highest turbulent kinetic energy appears at a distance of (7·5 to 8·5)d. Normalized distributions of the turbulent quantities are in good agreement with known data on the developed region of jets issuing from short nozzles.

Impact of fluid turbulent shear stress on failure surface of reservoir bank landslide

2018 ◽  
Vol 11 (22) ◽  
Author(s):  
Xuan Zhang ◽  
Liang Chen ◽  
Faming Zhang ◽  
Chengteng Lv ◽  
Yi feng Zhou
Keyword(s):  
Shear Stress ◽  
Failure Surface ◽  
Turbulent Shear ◽  
Turbulent Shear Stress

Effects of Concave Curvature on Boundary Layer Transition Under High Free-Stream Turbulence Conditions

2001 ◽  
Author(s):  
Michael P. Schultz ◽  
Ralph J. Volino
Keyword(s):  
Boundary Layer ◽  
Free Stream ◽  
Turbulent Transport ◽  
Boundary Layer Transition ◽  
Transitional Flow ◽  
Turbulent Shear ◽  
Radius Of Curvature ◽  
Layer Transition ◽  
Free Stream Turbulence ◽  
Turbulent Shear Stress

An experimental investigation has been carried out on a transitional boundary layer subject to high (initially 9%) free-stream turbulence, strong acceleration K=ν/Uw2dUw/dxas high as9×10-6, and strong concave curvature (boundary layer thickness between 2% and 5% of the wall radius of curvature). Mean and fluctuating velocity as well as turbulent shear stress are documented and compared to results from equivalent cases on a flat wall and a wall with milder concave curvature. The data show that curvature does have a significant effect, moving the transition location upstream, increasing turbulent transport, and causing skin friction to rise by as much as 40%. Conditional sampling results are presented which show that the curvature effect is present in both the turbulent and non-turbulent zones of the transitional flow.

Contribution towards a Reynolds-stress closure for low-Reynolds-number turbulence

1976 ◽  
Vol 74 (4) ◽  
pp. 593-610 ◽  
Author(s):  
K. Hanjalić ◽  
B. E. Launder
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Reynolds Stress ◽  
Dissipation Rate ◽  
Numerical Solutions ◽  
Low Reynolds Number ◽  
Transport Processes ◽  
Turbulent Shear ◽  
Turbulent Shear Stress ◽  
Low Reynolds

The problem of closing the Reynolds-stress and dissipation-rate equations at low Reynolds numbers is considered, specific forms being suggested for the direct effects of viscosity on the various transport processes. By noting that the correlation coefficient$\overline{uv^2}/\overline{u^2}\overline{v^2} $is nearly constant over a considerable portion of the low-Reynolds-number region adjacent to a wall the closure is simplified to one requiring the solution of approximated transport equations for only the turbulent shear stress, the turbulent kinetic energy and the energy dissipation rate. Numerical solutions are presented for turbulent channel flow and sink flows at low Reynolds number as well as a case of a severely accelerated boundary layer in which the turbulent shear stress becomes negligible compared with the viscous stresses. Agreement with experiment is generally encouraging.

scholarly journals Numerical Evidence of Turbulence Generated by Nonbreaking Surface Waves

2015 ◽  
Vol 45 (1) ◽  
pp. 174-180 ◽  
Author(s):  
Wu-ting Tsai ◽  
Shi-ming Chen ◽  
Guan-hung Lu
Keyword(s):  
Surface Waves ◽  
Water Surface ◽  
Nonlinear Boundary Conditions ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Langmuir Turbulence ◽  
Near Surface ◽  
Order Of Magnitude ◽  
Turbulence Production ◽  
Wave Induced

AbstractNumerical simulation of monochromatic surface waves propagating over a turbulent field is conducted to reveal the mechanism of turbulence production by nonbreaking waves. The numerical model solves the primitive equations subject to the fully nonlinear boundary conditions on the exact water surface. The result predicts growth rates of turbulent kinetic energy consistent with previous measurements and modeling. It also validates the observed horizontal anisotropy of the near-surface turbulence that the spanwise turbulent intensity exceeds the streamwise component. Such a flow structure is found to be attributed to the formation of streamwise vortices near the water surface, which also induces elongated surface streaks. The averaged spacing between the streaks and the depth of the vortical cells approximates that of Langmuir turbulence. The strength of the vortices arising from the wave–turbulence interaction, however, is one order of magnitude less than that of Langmuir cells, which arises from the interaction between the surface waves and the turbulent shear flow. In contrast to Langmuir turbulence, production from the Stokes shear does not dominate the energetics budget in wave-induced turbulence. The dominant production is the advection of turbulence by the velocity straining of waves.

Conditional Sampling in a Transitional Boundary Layer Under High Freestream Turbulence Conditions

2003 ◽  
Vol 125 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Ralph J. Volino ◽  
Michael P. Schultz ◽  
Christopher M. Pratt
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Streamwise Velocity ◽  
Turbulent Shear ◽  
Conditional Sampling ◽  
Freestream Turbulence ◽  
Mean Velocity ◽  
Transitional Boundary Layer ◽  
Turbulent Shear Stress ◽  
Order Of Magnitude

Conditional sampling has been performed on data from a transitional boundary layer subject to high (initially 9%) freestream turbulence and strong (K=ν/U∞2dU∞/dx as high as 9×10−6) acceleration. Methods for separating the turbulent and nonturbulent zone data based on the instantaneous streamwise velocity and the turbulent shear stress were tested and found to agree. Mean velocity profiles were clearly different in the turbulent and nonturbulent zones, and skin friction coefficients were as much as 70% higher in the turbulent zone. The streamwise fluctuating velocity, in contrast, was only about 10% higher in the turbulent zone. Turbulent shear stress differed by an order of magnitude, and eddy viscosity was three to four times higher in the turbulent zone. Eddy transport in the nonturbulent zone was still significant, however, and the nonturbulent zone did not behave like a laminar boundary layer. Within each of the two zones there was considerable self-similarity from the beginning to the end of transition. This may prove useful for future modeling efforts.

Abstract 329: The Role of TIE1 in Flow Mediated Lymphatic Vessel Remodeling and Valvulogenesis

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Cristina Harmelink ◽  
Bin Zhou ◽  
Xianghu Qu ◽  
H. Scott Baldwin
Keyword(s):  
Network Formation ◽  
Lymphatic Vessels ◽  
Mechanical Stimulus ◽  
Turbulent Shear ◽  
Branch Points ◽  
Turbulent Shear Stress ◽  
Valve Development ◽  
Lymphatic Vasculature ◽  
Cellular Machinery ◽  
Molecular Landscape

Recently, it has been shown that the mechanical stimulus of turbulent shear stress caused by onset of lymph flow is required for lymphatic remodeling, maturation, and lymphatic valve (LV) development. Homeostasis of the adult lymphatic vasculature also relies on flow-mediated signal transduction. However, the cellular machinery responsible for transducing mechanosensory signals required for lymphatic network formation and maintenance is unknown. Our laboratory has previously shown that TIE1 is at least partially responsible for mechanotransduction of turbulent flow required for initiation and maintenance of atherosclerotic plaque formation at the branch points of systemic vasculature in the adult animal. Moreover, TIE1 is expressed throughout lymphatic vasculature during mouse embryogenesis into adulthood, with enrichment in LVs. To circumvent the embryonic lethality caused by global Tie1 disruption, we conditionally deleted Tie1 using Nfatc1Cre. Nfatc1Cre drives recombination in lymphatic endothelial cells, with strong expression in the LVs. Nfatc1Cre:Tie1fl/fl mutants survive to birth but accumulate chyle in the peritoneal and pleural cavities by postnatal day 2. The lymphatic vessels in the mutants are dilated and tortuous, and do not undergo normal hierarchical remodeling. The constrictions that normally indicate intraluminal valve development are lacking in the mutant lymphatic vessels. Underlying these defects in the Nfatc1Cre:Tie1fl/fl mutants is loss of the normal molecular landscape associated with lymphatic patterning and valvulogenesis. Therefore, we hypothesize that Tie1 orchestrates the mechanotransduction necessary for intraluminal LV development and postnatal maintenance.

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