Visualization and measurement of supersonic jet flow field evolution issuing from a rectangular nozzle with aft-deck

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040092
Author(s):  
Yun Jiao ◽  
Chengpeng Wang ◽  
Wenshuo Wang ◽  
Keming Cheng
Keyword(s):  
Shear Stress ◽  
Flow Visualization ◽  
Near Field ◽  
Pressure Ratio ◽  
Supersonic Jet ◽  
Surface Flow ◽  
Rectangular Nozzle ◽  
Great Consistency ◽  
Oil Flow ◽  
Oil Flow Visualization

An experimental study is reported of supersonic jet surface flow structure visualization and wall shear stress field measurement issuing from a rectangular nozzle with aft-deck. The near-field surface flow structures evolution from over-expansion to under-expansion with the increase of nozzle pressure ratio (NPR) are successfully captured by surface oil flow visualization and shear sensitive liquid crystal coating (SSLCC) technique. The quantitative measurement result of shear stress vector field obtained by SSLCC shows that shear stress directions change significantly across the shock wave and expansion fans, while the magnitudes of shear stress have no obvious changes. Surface streamlines calculated by SSLCC image keep great consistency with the streamlines visualized using oil flow technique, which demonstrates the accuracy and potential application of SSLCC in supersonic jet surface flow visualization.

Investigation of Supersonic Jet Interaction With Hypersonic Cross Flow

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
S. L. N. Desikan ◽  
R. Saravanan ◽  
S. Subramanian ◽  
A. E. Sivararamakrishnan ◽  
S. Pandian
Keyword(s):  
Pressure Ratio ◽  
Supersonic Jet ◽  
Cross Flow ◽  
Injection Port ◽  
Strong Function ◽  
Jet Interaction ◽  
Oil Flow ◽  
Flow Features ◽  
Horseshoe Vortices ◽  
Oil Flow Visualization

This paper presents the interaction of a highly underexpanded supersonic jet of Mjet = 3.19 with hypersonic cross flow (M∞ = 6). The jet interaction flowfield was studied through wall static pressure measurement, Schlieren, and oil flow visualization. The results clearly demonstrate that flow separation is a strong function of jet pressure ratio (PR). To understand the overall flow physics, numerical simulations were also carried out. The flow features such as primary, secondary, tertiary, and quaternary vortex in separated boundary layer, horseshoe vortices, and its foot print downstream of the injection port were predicted well.

Numerical Simulation of Supersonic Jet Control by Tabs with Slanted Perforation

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
G. Ezhilmaran ◽  
Suresh Chandra Khandai ◽  
Yogesh Kumar Sinha ◽  
S. Thanigaiarasu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Near Field ◽  
Pressure Ratio ◽  
Supersonic Jet ◽  
Pressure Gradients ◽  
Nozzle Pressure Ratio ◽  
Nozzle Pressure ◽  
Jet Control ◽  
Different Diameters

Abstract This paper presents the numerical simulation of Mach 1.5 supersonic jet with perforated tabs. The jet with straight perforation tab was compared with jets having slanted perforated tabs of different diameters. The perforation angles were kept as 0° and 10° with respect to the axis of the nozzle. The blockage areas of the tabs were 4.9 %, 4.9 % and 2.4 % for straight perforation, 10° slanted perforation ( {{{\Phi }}_{\ }} = 1.3 mm) and 10° slanted perforation ( {{{\Phi }}_{\ }} = 1.65 mm) respectively. The 3-D numerical simulations were carried out using the software. The mixing enhancements caused by these tabs were studied in the presence of adverse and favourable pressure gradients, corresponding to nozzle pressure ratio (NPR) of 3, 3.7 and 5. For Mach number 1.5 jet, NPR 3 corresponds to 18.92 % adverse pressure gradients and NPR 5 corresponds to 35.13 % favourable pressure gradients. The centerline Mach number of the jet with slanted perforations is found to decay at a faster rate than uncontrolled nozzle and jet with straight perforation tab. Mach number plots were obtained at both near-field and far field downstream locations. There is 25 % and 65 % reduction in jet core length were observed for the 0° and 10° perforated tabs respectively in comparison to uncontrolled jet.

Studies of Flow Topology around Hemisphere at Transonic Speeds Using Time-Resolved Oil Flow Visualization

2016 ◽  
Author(s):  
Stanislav Gordeyev ◽  
Alexander Vorobiev ◽  
Eric J. Jumper ◽  
Sivaram P. Gogineni ◽  
Donald J. Wittich
Keyword(s):  
Flow Visualization ◽  
Flow Topology ◽  
Time Resolved ◽  
Oil Flow ◽  
Oil Flow Visualization

scholarly journals Effect of vortex generator on the flow field over a conventional delta wing in subsonic flow condition at higher angles of attack

2021 ◽  
Vol 49 (2) ◽  
pp. 395-400
Author(s):  
Manthan Patil ◽  
Rajesh Gawade ◽  
Shubham Potdar ◽  
Khushabu Nadaf ◽  
Sanoj Suresh ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Visualization ◽  
Drag Coefficient ◽  
Subsonic Flow ◽  
Delta Wing ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Vortex Generator ◽  
Oil Flow ◽  
Oil Flow Visualization

Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.

A Study of the Leading Edge Vortex and Tip Vortex on Prop-Fan Blades

1987 ◽  
Vol 109 (3) ◽  
pp. 325-331 ◽  
Author(s):  
C. M. Vaczy ◽  
D. C. McCormick
Keyword(s):  
Flow Visualization ◽  
Systematic Study ◽  
Leading Edge ◽  
Lower Surface ◽  
Tip Vortex ◽  
Leading Edge Vortex ◽  
Edge Loading ◽  
Oil Flow ◽  
Oil Flow Visualization ◽  
Edge Vortex

An oil flow visualization study was conducted on the blades of a counterrotating prop-fan model, the CRP-X1. A kink in the oil streaks was interpreted as an indication of the leading edge vortex reattachment line. The leading edge vortex was found to be on the lower surface for cases with negative leading edge loading and on the upper surface for cases with positive leading edge loading. For most cases, the leading edge vortex merged with a tip vortex. The results presented here represent the first systematic study of this phenomenon.

Oil-flow visualization on a SWT-2.3-101 wind turbine

2011 ◽  
Author(s):  
Paul Medina ◽  
Scott Schreck ◽  
Jeppe Johansen ◽  
Lee Fingersh
Keyword(s):  
Flow Visualization ◽  
Wind Turbine ◽  
Oil Flow ◽  
Oil Flow Visualization

Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part III: TIP Cooling

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
P. J. Newton ◽  
G. D. Lock ◽  
S. K. Krishnababu ◽  
H. P. Hodson ◽  
W. N. Dawes ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Flux ◽  
Flow Visualization ◽  
Film Cooling ◽  
Separation Bubble ◽  
Axial Flow ◽  
Tip Leakage Flow ◽  
Oil Flow ◽  
Oil Flow Visualization

Contours of heat transfer coefficient and effectiveness have been measured on the tip of a generic cooled turbine blade, using the transient liquid crystal technique. The experiments were conducted at an exit Reynolds number of 2.3×105 in a five-blade linear cascade with tip clearances of 1.6% and 2.8% chord and featuring engine-representative cooling geometries. These experiments were supported by oil-flow visualization and pressure measurements on the tip and casing and by flow visualization calculated using CFX, all of which provided insight into the fluid dynamics within the gap. The data were compared with measurements taken from the uncooled tip gap, where the fluid dynamics is dominated by flow separation at the pressure-side edge. Here, the highest levels of heat transfer are located where the flow reattaches on the tip surface downstream of the separation bubble. A quantitative assessment using the net heat flux reduction (NHFR) revealed a significant benefit of ejecting coolant inside this separation bubble. Engine-representative blowing rates of approximately 0.6–0.8 resulted in good film-cooling coverage and a reduction in heat flux to the tip when compared to both the flat tip profile and the squealer and cavity tip geometries discussed in Part 1 of this paper. Of the two novel coolant-hole configurations studied, injecting the coolant inside the separation bubble resulted in an improved NHFR when compared to injecting coolant at the location of reattachment.

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