Experimental analysis of an under-expanded jet interacting with a tangential flat plate: Flow visualizations and wall pressure statistics

2022 ◽  
Vol 130 ◽  
pp. 110474
Author(s):  
Roberto Camussi ◽  
Mohsin K. Ahmad ◽  
Stefano Meloni ◽  
Elisa de Paola ◽  
Alessandro Di Marco
Keyword(s):  
Flat Plate ◽  
Experimental Analysis ◽  
Wall Pressure ◽  
Flow Visualizations

Aerodynamic Measurements on the Interaction of Secondary Jets and Separation Bubble

2012 ◽  
Author(s):  
A. Samson ◽  
S. Sarkar
Keyword(s):  
Flat Plate ◽  
Large Scale ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Leading Edge ◽  
Bubble Interactions ◽  
Separated Shear Layer ◽  
Bubble Length ◽  
Flow Visualizations ◽  
Turbulence Generation

The dynamics of separation bubble under the influence of continuous jets ejected near the semi-circular leading edge of a flat plate is presented. Two different streamwise injection angles 30° and 60° and velocity ratios 0.5 and 1 for Re = 25000 and 55000 (based on the leading-edge diameter) are considered here. The flow visualizations illustrating jet and separated layer interactions have been carried out with PIV. The objective of this study is to understand the mutual interactions of separation bubble and the injected jets. It is observed that flow separates at the blending point of semi-circular arc and flat plate. The separated shear layer is laminar up to 20% of separation length after which perturbations are amplified and grows in the second-half of the bubble leading to breakdown and reattachment. Blowing has significantly affected the bubble length and thus, turbulence generation. Instantaneous flow visualizations supports the unsteadiness and development of three-dimensional motions leading to formation of Kelvin-Helmholtz rolls and shedding of large-scale vortices due to jet and bubble interactions. In turn, it has been seen that both the spanwise and streamwise dilution of injected air is highly influenced by the separation bubble.

Interaction Between the Underwater Explosion Bubble and the Structure

2008 ◽  
Author(s):  
A. M. Zhang ◽  
X. L. Yao ◽  
D. Y. Shi ◽  
J. Li
Keyword(s):  
Free Surface ◽  
Flat Plate ◽  
Dynamic Characteristics ◽  
Potential Flow ◽  
Underwater Explosion ◽  
Wall Pressure ◽  
Severe Damage ◽  
Plastic Structure ◽  
Pressure Peak ◽  
Great Damage

Based on the potential-flow assumption, BEM is applied to simulate the dynamic characteristics of underwater explosion bubble near boundaries and solve the interaction of bubble and elastic-plastic structure by coupling with FEM. A complete 3D program of underwater bubble analysis (UBA) is developed and the calculated error is within 10%. With this program, flat plate, cylinder and other simple structures are analyzed; the damages caused by retarded flow, pulsating pressure and jet and other loads on the structures are calculated, including different cases with free surface or without free surface. Results show that bubbles can cause great damage, and the specific cases can even cause greater damage. From the wall pressure and the stress curves of typical elements on the structure, it can be seen that the pressure peak occurs when the bubble collapses, which proves that the pressures caused by the bubble’s collapse and jet can result in great structure’s severe damage. It can provide reference for the research on the dynamic characteristics. The research in this paper aims to provide references for the correlated research on the dynamics of the underwater bubble.

Pressure and velocity measurements of an incompressible moderate Reynolds number jet interacting with a tangential flat plate

2015 ◽  
Vol 770 ◽  
pp. 247-272 ◽  
Author(s):  
A. Di Marco ◽  
M. Mancinelli ◽  
R. Camussi
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Scaling Laws ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Theoretical Modelling ◽  
Wall Pressure Fluctuations ◽  
Moderate Reynolds Number ◽  
The Mean ◽  
Pressure And Velocity Measurements

The statistical properties of wall pressure fluctuations generated on a rigid flat plate by a tangential incompressible single stream jet are investigated experimentally. The study is carried out at moderate Reynolds number and for different distances between the nozzle axis and the flat plate. The overall aerodynamic behaviour is described through hot wire anemometer measurements, providing the effect of the plate on the mean and fluctuating velocity. The pressure field acting on the flat plate was measured by cavity-mounted microphones, providing point-wise pressure signals in the stream-wise and span-wise directions. Statistics of the wall pressure fluctuations are determined in terms of time-domain and Fourier-domain quantities and a parametric analysis is conducted in terms of the main geometrical length scales. Possible scaling laws of auto-spectra and coherence functions are presented and implications for theoretical modelling are discussed.

Steady State Analysis on Efficiency Improving Methods for Series Flat Plate Solar Water Heaters

2014 ◽  
Vol 592-594 ◽  
pp. 1784-1788
Author(s):  
M. Sridharan ◽  
E. Siva Prakash ◽  
N. Prasanna
Keyword(s):  
Steady State ◽  
Theoretical Analysis ◽  
Flat Plate ◽  
Experimental Analysis ◽  
New Combination ◽  
Improve Performance ◽  
Steady State Analysis ◽  
Water Heaters ◽  
Different Types ◽  
Solar Water Heaters

Now a day’s different types of solar flat plate collectors are in use. Out of which only few type of collectors proved their performance by producing better results of expected level. In this paper a new set of collectors are combined as mean to improve performance of series SFPC collectors available in market now a days. In such new combination a collector with reduced overall loss coefficient was used to improve the efficiency of the existing system. New collector with zig-zag flow pattern gives a slight change in flow path. Thus the objective of this experimental analysis is to improve efficiency with new set of series FPC by comparing with existing series FPC. Experimental results obtained give better and higher results suggested by theoretical analysis.

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