scholarly journals Effect of Vortex-Wake Interaction on Vortex-Rotor Interference and on Rotor Trim

2021 ◽  
pp. 407-417
Author(s):  
Berend G. van der Wall
Keyword(s):  
Vortex Wake ◽  
Wake Interaction ◽  
Rotor Trim

Surface pressure measurements on a body subject to vortex wake interaction

AIAA Journal ◽  
1989 ◽  
Vol 27 (5) ◽  
pp. 569-574 ◽  
Author(s):  
A. G. Brand ◽  
H. M. McMahon ◽  
N. M. Komerath
Keyword(s):  
Surface Pressure ◽  
Vortex Wake ◽  
Pressure Measurements ◽  
Wake Interaction ◽  
Body Subject

scholarly journals Volumetric imaging of fish locomotion

2011 ◽  
Vol 7 (5) ◽  
pp. 695-698 ◽  
Author(s):  
Brooke E. Flammang ◽  
George V. Lauder ◽  
Daniel R. Troolin ◽  
Tyson E. Strand
Keyword(s):  
Imaging System ◽  
New Technology ◽  
Three Dimensional ◽  
Ring Vortex ◽  
Vortex Wake ◽  
Volumetric Imaging ◽  
Fish Locomotion ◽  
Wake Interaction ◽  
Fluid Environment ◽  
Complex Fluid

Fishes use multiple flexible fins in order to move and maintain stability in a complex fluid environment. We used a new approach, a volumetric velocimetry imaging system, to provide the first instantaneous three-dimensional views of wake structures as they are produced by freely swimming fishes. This new technology allowed us to demonstrate conclusively the linked ring vortex wake pattern that is produced by the symmetrical (homocercal) tail of fishes, and to visualize for the first time the three-dimensional vortex wake interaction between the dorsal and anal fins and the tail. We found that the dorsal and anal fin wakes were rapidly (within one tail beat) assimilated into the caudal fin vortex wake. These results show that volumetric imaging of biologically generated flow patterns can reveal new features of locomotor dynamics, and provides an avenue for future investigations of the diversity of fish swimming patterns and their hydrodynamic consequences.

Unsteady Numerical Simulation of Shock Systems in Vaneless Counter-Rotating Turbine

2005 ◽  
Author(s):  
Huishe Wang ◽  
Qingjun Zhao ◽  
Xiaolu Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Nozzle Design ◽  
Suction Surface ◽  
Rotor Wake ◽  
Wake Interaction ◽  
Unsteady Numerical Simulation ◽  
Almost All

A detailed unsteady numerical simulation has been carried out to investigate the shock systems in the high pressure (HP) turbine rotor and unsteady shock-wake interaction between coupled blade rows in a 1+1/2 counter-rotating turbine (VCRT). For the VCRT HP rotor, due to the convergent-divergent nozzle design, along almost all the span, fishtail shock systems appear after the trailing edge, where the pitch averaged relative Mach number is exceeding the value of 1.4 and up to 1.5 approximately (except the both endwalls). A group of pressure waves create from the suction surface after about 60% axial chord in the VCRT HP rotor, and those waves interact with the inner-extending shock (IES). IES first impinges on the next HP rotor suction surface and its echo wave is strong enough and cannot be neglected, then the echo wave interacts with the HP rotor wake. Strongly influenced by the HP rotor wake and LP rotor, the HP rotor outer-extending shock (OES) varies periodically when moving from one LP rotor leading edge to the next. In VCRT, the relative Mach numbers in front of IES and OES are not equal, and in front of IES, the maximum relative Mach number is more than 2.0, but in front of OES, the maximum relative Mach number is less than 1.9. Moreover, behind IES and OES, the flow is supersonic. Though the shocks are intensified in VCRT, the loss resulted in by the shocks is acceptable, and the HP rotor using convergent-divergent nozzle design can obtain major benefits.

scholarly journals Vortex Wake from Tapered and Stepped Circular Cylinders in a Uniform Flow.

1993 ◽  
Vol 59 (559) ◽  
pp. 684-690 ◽  
Author(s):  
Junichiro Fukutomi ◽  
Yoshiyuki Nakase ◽  
Misao Takikawa
Keyword(s):  
Uniform Flow ◽  
Circular Cylinders ◽  
Vortex Wake

Note on the swimming of slender fish

1960 ◽  
Vol 9 (2) ◽  
pp. 305-317 ◽  
Author(s):  
M. J. Lighthill
Keyword(s):  
Swimming Speed ◽  
Critical Value ◽  
Slender Body ◽  
Vortex Wake ◽  
Frictional Drag ◽  
Slender Body Theory ◽  
Propulsive Efficiency ◽  
Deformable Bodies ◽  
Work Done ◽  
Body Theory

The paper seeks to determine what transverse oscillatory movements a slender fish can make which will give it a high Froude propulsive efficiency, $\frac{\hbox{(forward velocity)} \times \hbox{(thrust available to overcome frictional drag)}} {\hbox {(work done to produce both thrust and vortex wake)}}.$ The recommended procedure is for the fish to pass a wave down its body at a speed of around $\frac {5} {4}$ of the desired swimming speed, the amplitude increasing from zero over the front portion to a maximum at the tail, whose span should exceed a certain critical value, and the waveform including both a positive and a negative phase so that angular recoil is minimized. The Appendix gives a review of slender-body theory for deformable bodies.

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