Experimental investigation of influence of Reynolds number on synthetic jet vortex rings impinging onto a solid wall

2016 ◽  
Vol 58 (1) ◽  
Author(s):  
Yang Xu ◽  
GuoSheng He ◽  
Varun Kulkarni ◽  
JinJun Wang
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Solid Wall ◽  
Synthetic Jet ◽  
Vortex Rings

scholarly journals The effect of a parallel free surface upon a submerged shallow synthetic jet

2020 ◽  
Author(s):  
Abhay Kumar ◽  
Ashish Karn
Keyword(s):  
Reynolds Number ◽  
Free Surface ◽  
Vortex Ring ◽  
Water Surface ◽  
Primary Objective ◽  
Synthetic Jet ◽  
Vortex Rings ◽  
Beam Laser ◽  
Jet Trajectory ◽  
Water Depths

The interaction of a submerged shallow synthetic jet with a parallel free surface has gathered substantial interest, owing to its relevance to the operation of marine vehicles viz. ships that move close to the water surface. However, despite exhaustive research on the perturbation on a free surface, very few studies have experimentally investigated the effect of unconfined water surface height on the evolution and propagation of a submerged synthetic jet. This study experimentally investigates a synthetic jet submerged in a quiescent flow at shallow depths ejecting parallel to the free surface, through qualitative analysis and quantitative measurements. The qualitative study includes the visualization of the flow using Plane Laser Induced Fluorescence (PLIF) technique, whereas the velocity measurements are carried out by a five-beam Laser Doppler Velocimetry (LDV) probe. The primary objective of these analysis and measurements is to gain a physical insight into the characteristics of vortex ring in a synthetic jet ejected from a fixed orifice at different water depths and at varying Reynolds number. Our studies indicate that the behavior of the vortex rings drastically changes as the depth of the jet crosses a certain threshold. Although no significant change in the path of synthetic jet is observed beyond a threshold depth in our experiments, the jet trajectory shows an interesting dependence on the Reynolds number based on circulation for shallow water depths. It has been found that in the shallow depths, the vortex ring drifts upwards and interacts with the free surface at lower Reynolds number, whereas for larger Reynolds number, the vortex ring rebounds near the free surface and moves downward. Based on our observations, it can be concluded that the phenomenon of upward/downward flection of vortex rings depends both upon its circulation and water depth.

Experimental investigation on the impingement of synthetic jet vortex rings onto a porous wall

2021 ◽  
Vol 33 (3) ◽  
pp. 035140
Author(s):  
Yang Xu ◽  
Zhi-Yu Li ◽  
Jin-Jun Wang
Keyword(s):  
Experimental Investigation ◽  
Porous Wall ◽  
Synthetic Jet ◽  
Vortex Rings

Electronic Cooling Using Synthetic Jet Impingement

2006 ◽  
Vol 128 (9) ◽  
pp. 897-907 ◽  
Author(s):  
Anna Pavlova ◽  
Michael Amitay
Keyword(s):  
Reynolds Number ◽  
Low Frequency ◽  
Jet Impingement ◽  
Constant Heat Flux ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Electronic Cooling ◽  
Vortex Rings ◽  
Jet Formation ◽  
Image Velocimetry

The efficiency and mechanisms of cooling a constant heat flux surface by impinging synthetic jets were investigated experimentally and compared to cooling with continuous jets. Effects of jet formation frequency and Reynolds number at different nozzle-to-surface distances (H∕d) were investigated. High formation frequency (f=1200Hz) synthetic jets were found to remove heat better than low frequency (f=420Hz) jets for small H∕d, while low frequency jets are more effective at larger H∕d. Moreover, synthetic jets are about three times more effective in cooling than continuous jets at the same Reynolds number. Using particle image velocimetry, it was shown that the higher formation frequency jets are associated with breakdown and merging of vortices before they impinge on the surface. For the lower frequency jets, the wavelength between coherent structures is larger such that vortex rings impinge on the surface separately.

Experimental Investigation on Blunt-Edged UTM Delta Wing VFE-2 Configurations at Low Reynolds Number

2018 ◽  
Vol 12 (3) ◽  
pp. 255
Author(s):  
Muhammad Zal Aminullah Daman Huri ◽  
Shabudin Bin Mat ◽  
Mazuriah Said ◽  
Shuhaimi Mansor ◽  
Md. Nizam Dahalan ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Delta Wing ◽  
Low Reynolds Number ◽  
Low Reynolds

scholarly journals Experimental investigation of interfacial mass transfer mechanisms for a confined high‐reynolds‐number bubble rising in a thin gap

AIChE Journal ◽  
2016 ◽  
Vol 63 (6) ◽  
pp. 2394-2408 ◽  
Author(s):  
Matthieu Roudet ◽  
Anne‐Marie Billet ◽  
Sébastien Cazin ◽  
Frédéric Risso ◽  
Véronique Roig
Keyword(s):  
Mass Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
High Reynolds Number ◽  
Interfacial Mass Transfer ◽  
Bubble Rising ◽  
High Reynolds ◽  
Transfer Mechanisms

Experimental investigation of a synthetic jet impinging on a fixed wall

2013 ◽  
Vol 54 (5) ◽  
Author(s):  
Yang Xu ◽  
Li-Hao Feng ◽  
Jin-Jun Wang
Keyword(s):  
Experimental Investigation ◽  
Synthetic Jet

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

Sign in / Sign up

Export Citation Format

Share Document