Unsteady free-surface wave-induced boundary-layer separation for a surface-piercing NACA 0024 foil: Towing tank experiments

2006 ◽  
Vol 22 (1) ◽  
pp. 77-98 ◽  
Author(s):  
B. Metcalf ◽  
J. Longo ◽  
S. Ghosh ◽  
F. Stern
Keyword(s):  
Boundary Layer ◽  
Free Surface ◽  
Surface Wave ◽  
Boundary Layer Separation ◽  
Towing Tank ◽  
Layer Separation ◽  
Free Surface Wave ◽  
Wave Induced

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.

Shock-wave-induced turbulent boundary-layer separation at hypersonicspeeds

1975 ◽  
Author(s):  
C. HORSTMAN ◽  
M. KUSSOY ◽  
T. COAKLEY ◽  
M. RUBESIN ◽  
J. MARVIN
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Separation ◽  
Layer Separation ◽  
Wave Induced

DES and RANS of Unsteady Free-Surface Wave Induced Separation

2004 ◽  
Author(s):  
Tao Xing ◽  
Mani Kandasamy ◽  
Robert Wilson ◽  
Fred Stern
Keyword(s):  
Free Surface ◽  
Surface Wave ◽  
Free Surface Wave ◽  
Wave Induced

Oscillations of a shock wave induced by boundary layer separation

1991 ◽  
Vol 25 (4) ◽  
pp. 639-641 ◽  
Author(s):  
V. N. Bibko ◽  
B. M. Efimtsov ◽  
V. G. Korkach ◽  
V. B. Kuznetsov
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Boundary Layer Separation ◽  
Layer Separation ◽  
Wave Induced

Wave-Induced Boundary Layer Separation in the Lee of the Medicine Bow Mountains. Part I: Observations*

2015 ◽  
Vol 72 (12) ◽  
pp. 4845-4863 ◽  
Author(s):  
Jeffrey R. French ◽  
Samuel J. Haimov ◽  
Larry D. Oolman ◽  
Vanda Grubišić ◽  
Stefano Serafin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Vertical Plane ◽  
Boundary Layer Separation ◽  
Mountain Waves ◽  
Near Surface ◽  
Layer Separation ◽  
Medicine Bow Mountains ◽  
Vertical Winds ◽  
Wave Induced

Abstract Two cases of mountain waves, rotors, and the associated turbulence in the lee of the Medicine Bow Mountains in southeastern Wyoming are investigated in a two-part study using aircraft observations and numerical simulations. In Part I, observations from in situ instruments and high-resolution cloud radar on board the University of Wyoming King Air aircraft are presented and analyzed. Measurements from the radar compose the first direct observations of wave-induced boundary layer separation. The data from these two events show some striking similarities but also significant differences. In both cases, rotors were observed; yet one looks like a classical lee-wave rotor, while the other resembles an atmospheric hydraulic jump with midtropospheric gravity wave breaking aloft. High-resolution (30 × 30 m2) dual-Doppler syntheses of the two-dimensional velocity fields in the vertical plane beneath the aircraft reveal the boundary layer separation, the scale and structure of the attendant rotors, and downslope windstorms. In the stronger of the two events, near-surface winds upwind of the boundary layer separation reached 35 m s−1, and vertical winds were in excess of 10 m s−1. Moderate to strong turbulence was observed within and downstream of these regions. In both cases, the rotor extended horizontally 5–10 km and vertically 2–2.5 km. Horizontal vorticity within the rotor zone reached 0.2 s−1. Several subrotors from 500 to 1000 m in diameter were identified inside the main rotor in one of the cases. Part II presents a modeling study and investigates the kinematic structure and the dynamic evolution of these two events.

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