Free-Surface Effects on Ship Boundary Layers and Wakes

1992 ◽  
Author(s):  
Fred Stern
Keyword(s):  
Free Surface ◽  
Boundary Layers ◽  
Surface Effects

Free surface effects on the recrystallization of compressed, stable, Al-Mn single crystals

2018 ◽  
Vol 146 ◽  
pp. 135-148 ◽  
Author(s):  
Magdalena M. Miszczyk ◽  
Henryk Paul ◽  
Julian H. Driver
Keyword(s):  
Free Surface ◽  
Single Crystals ◽  
Surface Effects

Towed Underwater SPIV Measurement of Flow Fields Around a Surface-Piercing Cylinder With Free Surface Effects

2015 ◽  
Author(s):  
Jeonghwa Seo ◽  
Bumwoo Han ◽  
Shin Hyung Rhee
Keyword(s):  
Boundary Layer ◽  
Free Surface ◽  
Surface Wave ◽  
Flow Field ◽  
Cross Section ◽  
Surface Effects ◽  
Flow Fields ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Wave Induced

Effects of free surface on development of turbulent boundary layer and wake fields were investigated. By measuring flow field around a surface piercing cylinder in various advance speed conditions in a towing tank, free surface effects were identified. A towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system was used to measure the flow field under free surface. The cross section of the test model was water plane shape of the Wigley hull, of which longitudinal length and width were 1.0 m and 100 mm, respectively. With sharp bow shape and slender cross section, flow separation was not expected in two-dimensional flow. Flow fields near the free-surface and in deep location that two-dimensional flow field was expected were measured and compared to identify free-surface effects. Some planes perpendicular to longitudinal direction near the model surface and behind the model were selected to track development of turbulent boundary layer. Froude numbers of the test conditions were from 0.126 to 0.40 and corresponding Reynolds numbers were from 395,000 to 1,250,000. In the lowest Froude number condition, free-surface wave was hardly observed and only free surface effects without surface wave could be identified while violent free-surface behavior due to wave-induced separation dominated the flow fields in the highest Froude number condition. From the instantaneous velocity fields, Time-mean velocity, turbulence kinetic energy, and flow structure derived by proper orthogonal decomposition (POD) were analyzed. As the free-surface effect, development of retarded wake, free-surface waves, and wave-induced separation were mainly observed.

Large Eddy Simulations of Taylor-Go¨rtler Instabilities in Transitional and Turbulent Boundary Layers

2010 ◽  
Author(s):  
Sergej Gordeev ◽  
Robert Stieglitz ◽  
Volker Heinzel
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Liquid Metal ◽  
Boundary Layers ◽  
High Power ◽  
Turbulent Boundary Layers ◽  
Numerical Predictions ◽  
Back Plate ◽  
Exit Nozzle ◽  
Large Eddy

Free surface liquid metal targets are considered in several high power targets as a tool to produce secondary particles, since their power density exceeds material sustainable limits. Many target designs consider due to the high power deposited in the liquid a concave formed back plate in order to yield a higher boiling point. Upstream the free surface target domain the liquid metal flow is conditioned by a nozzle. However, a back-wall curvature as well as a concave shaped exit nozzle contour can lead to the occurrence of secondary motions in the flow caused by Taylor-Go¨rtler (TG) instabilities. These motions may impact the hydrodynamic stability the flow and also lead to an undesired heat transfer from the hottest region produced within the liquid target towards the uncooled back plate. In this study, the suitability of the Large Eddy Simulation (LES) technique to simulate the formation, development and destruction TG instabilities in transitional and turbulent boundary layers was tested by comparing the simulation results with experimental data reported in literature. All comparisons exhibit a qualitative and quantitative good agreement between experimental data and numerical predictions regarding the mean flow parameters and unsteady large-scale structures caused by TG instabilities.

Free surface effects on the flow between conical cylinders

1999 ◽  
Vol 135 (1-2) ◽  
pp. 13-25 ◽  
Author(s):  
M. N. Noui-Mehidi ◽  
M. Wimmer
Keyword(s):  
Free Surface ◽  
Surface Effects

Prediction of hydrodynamic loading on a mini TLP with free surface effects

2006 ◽  
Vol 33 (2) ◽  
pp. 181-204 ◽  
Author(s):  
Bassam A. Younis ◽  
Vlado P. Przulj
Keyword(s):  
Free Surface ◽  
Surface Effects ◽  
Hydrodynamic Loading
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