scholarly journals The flow structure at interaction of gas jets with cross-flow in the supersonic combustor

2018 ◽  
Author(s):  
Marat Goldfeld ◽  
Maxim Golubev ◽  
Konstantin Timofeev
Keyword(s):  
Flow Structure ◽  
Cross Flow ◽  
Gas Jets

Numerical Investigation of Passive Flow Control Using Wavy Blades in a Highly-Loaded Compressor Cascade

2018 ◽  
Author(s):  
Bo Wang ◽  
Yanhui Wu ◽  
Kai Liu
Keyword(s):  
Numerical Investigation ◽  
Flow Structure ◽  
Cross Flow ◽  
Leading Edge ◽  
Control Flow ◽  
Streamwise Vortices ◽  
Compressor Cascade ◽  
Control Effect ◽  
Suction Surface ◽  
Highly Loaded

Driven by the need to control flow separations in highly loaded compressors, a numerical investigation is carried out to study the control effect of wavy blades in a linear compressor cascade. Two types of wavy blades are studied with wavy blade-A having a sinusoidal leading edge, while wavy blade-B having pitchwise sinusoidal variation in the stacking line. The influence of wavy blades on the cascade performance is evaluated at incidences from −1° to +9°. For the wavy blade-A with suitable waviness parameters, the cascade diffusion capacity is enhanced accompanied by the loss reduction under high incidence conditions where 2D separation is the dominant flow structure on the suction surface of the unmodified blade. For well-designed wavy blade-B, the improvement of cascade performance is achieved under low incidence conditions where 3D corner separation is the dominant flow structure on the suction surface of the baseline blade. The influence of waviness parameters on the control effect is also discussed by comparing the performance of cascades with different wavy blade configurations. Detailed analysis of the predicted flow field shows that both the wavy blade-A and wavy blade-B have capacity to control flow separation in the cascade but their control mechanism are different. For wavy blade-A, the wavy leading edge results in the formation of counter-rotating streamwise vortices downstream of trough. These streamwise vortices can not only enhance momentum exchange between the outer flow and blade boundary layer, but also act as the suction surface fence to hamper the upwash of low momentum fluid driven by cross flow. For wavy blade-B, the wavy surface on the blade leads to a reduction of the cross flow upwash by influencing the spanwise distribution of the suction surface static pressure and guiding the upwash flow.

Convergence of numerical simulations of turbulent wall-bounded flows and mean cross-flow structure of rectangular ducts

Meccanica ◽  
2016 ◽  
Vol 51 (12) ◽  
pp. 3025-3042 ◽  
Author(s):  
Ricardo Vinuesa ◽  
Cezary Prus ◽  
Philipp Schlatter ◽  
Hassan M. Nagib
Keyword(s):  
Numerical Simulations ◽  
Flow Structure ◽  
Cross Flow ◽  
Wall Bounded Flows ◽  
Turbulent Wall

Flow structure of the plane turbulent impinging jet in cross flow

2001 ◽  
Vol 39 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Meilan Qi ◽  
Zhicong Chen ◽  
Renshou Fu
Keyword(s):  
Flow Structure ◽  
Cross Flow ◽  
Impinging Jet ◽  
Jet In Cross Flow

Flow and Heat Transfer of Confined Impingement Jets Cooling

2000 ◽  
Author(s):  
Ting Wang ◽  
Mingjie Lin ◽  
Ronald S. Bunker
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flow Structure ◽  
Experimental Studies ◽  
Cross Flow ◽  
Jet Impingement ◽  
Target Surface ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Transfer Behavior

Experimental studies on heat transfer and flow structure in confined impingement jets were performed. The objective of this study was to investigate the detailed heat transfer coefficient distribution on the jet impingement target surface and flow structure in the confined cavity. The distribution of heat transfer coefficients on the target surface was obtained by employing the transient liquid crystal method coupled with a 3-D inverse transient conduction scheme under Reynolds number ranging from 1039 to 5175. The results show that the average heat transfer coefficients increased linearly with the Reynolds number as Nu = 0.00304 Pr0.42Re. The effects of cross flow on heat transfer were investigated. The flow structure were analyzed to gain insight into convective heat transfer behavior.

scholarly journals Gravitational Effects on Near-Field Flow Structure of Low-Density Gas Jets

AIAA Journal ◽  
2003 ◽  
Vol 41 (10) ◽  
pp. 1973-1979 ◽  
Author(s):  
Tze-Wing Yep ◽  
Ajay K. Agrawal ◽  
DeVon Griffin
Keyword(s):  
Flow Structure ◽  
Near Field ◽  
Low Density ◽  
Gravitational Effects ◽  
Gas Jets

scholarly journals 1046 FLOW STRUCTURE GENERATION BY MULTIPLE JETS IN SUPERSONIC CROSS-FLOW

2013 ◽  
Vol 2013.4 (0) ◽  
pp. _1046-1_-_1046-6_ ◽  
Author(s):  
Semlitsch Bernhard ◽  
Mihaescu Mihai ◽  
Gutmark Ephraim J. ◽  
Fuchs Laszlo
Keyword(s):  
Flow Structure ◽  
Cross Flow ◽  
Structure Generation ◽  
Multiple Jets

Flow Structure, Pressure Fluctuations and Resulting Vibrations Caused by the Interaction of a Turbulent Jet With Cross Flow Over a Flexible Flat Plate

2002 ◽  
Author(s):  
Shridhar Gopalan ◽  
Bruce M. Abraham ◽  
Joseph Katz
Keyword(s):  
Boundary Layer ◽  
Flow Structure ◽  
Velocity Ratio ◽  
Pressure Fluctuations ◽  
Cross Flow ◽  
Wall Pressure ◽  
Turbulent Jet ◽  
Pressure Measurements ◽  
Structural Vibrations ◽  
Wall Pressure Fluctuations

The objective of this study is to characterize the velocity, vorticity, wall pressure fluctuations and resulting structural vibrations caused by injection of a round, turbulent jet into a turbulent boundary layer. The experiments are performed in a quiet water channel with back ground noise well below the local pressure fluctuations. One of the channel walls is replaced by a vibration isolated, 1m long, aluminum plate from which the 1cm-diameter jet is injected. The cross flow velocity is fixed at 2 m/s and the velocity ratio, r (ratio of mean jet velocity to the cross flow), varies from 0.5 to 2.5 and Re based on cross flow and jet diameter is 20,000. High-resolution PIV is used to measure the flow field and high sensitivity, low-noise pressure sensors are used for the wall pressure measurements. The flush-mounted transducers are installed at several locations ranging from 2–15 diameters behind the jet. Auto-spectra of the pressure signals show that the effect of the jet is in the 15–100Hz range, and increase the wall pressure levels by 25dB for r=2.5. The fluctuations increase with velocity ratio and decrease with distance from the jet, although there is only a 6dB increase in overall levels at r=2.5 as compared to r=1. Hilbert-Huang “amplitude” spectrum shows the frequency content of the signal as it evolves in time, and is found to be a useful tool to characterize such unsteady phenomena. Velocity and pressure measurements have been performed simultaneously and thousands of frames have been recorded. Analysis of these frames demonstrates the relationship between the wall pressure fluctuations and the vortical structures. Several striking differences in the flow structure between high and low velocity ratios are described in the paper. Acceleration measurements describe the effect of the jet and cross flow on the vibrations of the side-wall. Cross flow boundary layer dominates structural vibrations below 1000Hz, and jet velocity effects are visible at 1000Hz–2000Hz. At higher jet velocities effects are seen even below 1000Hz and large narrow band frequency peaks occur. (CD ROM version includes color figures).

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