scholarly journals 2D Analysis for Computing Supersonic and Subsonic Flow Field by Using Schlieren Light.(Dept.M)

2021 ◽  
Vol 28 (1) ◽  
pp. 20-34
Author(s):  
Nabil Mostafa
Keyword(s):  
Flow Field ◽  
Subsonic Flow

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.

Analysis of Rotor-Rotor and Stator-Stator Interferences in Multi-Stage Turbomachines

2002 ◽  
Author(s):  
L. He ◽  
T. Chen ◽  
R. G. Wells ◽  
Y. S. Li ◽  
W. Ning
Keyword(s):  
Shock Waves ◽  
Flow Field ◽  
Transonic Flow ◽  
Subsonic Flow ◽  
Present Approach ◽  
Post Processing ◽  
Transonic Compressor ◽  
Multi Stage ◽  
Performance Variation

A nonlinear harmonic methodology is adopted to analyse interactions between adjacent stages in multi-stage compressors. Of particular interest are the effects of circumferential ‘aperiodic’ distributions and the relative circumferential positioning (‘clocking’) of blades. The main feature of the present approach is that both the aperiodic and clocking effects are very efficiently included with circumferential ‘steady’ harmonic disturbances. Consequently, a single run of the nonlinear harmonic solver using a single-passage domain can produce the whole annulus unsteady and aperiodic time-averaged flow field. In addition, performance variation at any clocking position can be obtained simply by post-processing the result. A case study is presented for a two and half stage transonic compressor, and the present results show much stronger rotor-rotor interaction than stator-stator interaction. A mechanism leading to strong rotor-rotor interference seems to be the interaction between upstream rotor wakes and the downstream rotor passage shock waves. A rotor-rotor clocking study illustrates a qualitatively different loss variation with respect to clocking position in a transonic flow compared to that in a subsonic flow.

Analysis of Rotor-Rotor and Stator-Stator Interferences in Multi-Stage Turbomachines

2002 ◽  
Vol 124 (4) ◽  
pp. 564-571 ◽  
Author(s):  
L. He ◽  
T. Chen ◽  
R. G. Wells ◽  
Y. S. Li ◽  
W. Ning
Keyword(s):  
Shock Waves ◽  
Flow Field ◽  
Transonic Flow ◽  
Subsonic Flow ◽  
Present Approach ◽  
Post Processing ◽  
Transonic Compressor ◽  
Multi Stage ◽  
Performance Variation

A nonlinear harmonic methodology is adopted to analyze interactions between adjacent stages in multi-stage compressors. Of particular interest are the effects of circumferential “aperiodic” distributions and the relative circumferential positioning (‘clocking’) of blades. The main feature of the present approach is that both the aperiodic and clocking effects are very efficiently included with circumferential “steady” harmonic disturbances. Consequently, a single run of the nonlinear harmonic solver using a single-passage domain can produce the whole annulus unsteady and aperiodic time-averaged flow field. In addition, performance variation at any clocking position can be obtained simply by post-processing the result. A case study is presented for a two-and-half-stage transonic compressor, and the present results show much stronger rotor-rotor interaction than stator-stator interaction. A mechanism leading to strong rotor-rotor interference seems to be the interaction between upstream rotor wakes and the downstream rotor passage shock waves. A rotor-rotor clocking study illustrates a qualitatively different loss variation with respect to clocking position in a transonic flow compared to that in a subsonic flow.

Acoustic Computations Using Incompressible, Inviscid CFD Results as Input

1999 ◽  
Author(s):  
Sheryl M. Grace ◽  
Caroline K. Curtis
Keyword(s):  
Finite Difference ◽  
Flow Field ◽  
Difference Scheme ◽  
Acoustic Field ◽  
Incompressible Flow ◽  
Finite Difference Scheme ◽  
Subsonic Flow ◽  
Two Dimensional ◽  
Dimensional Problem ◽  
Grazing Flow

Abstract This paper presents preliminary results from an acoustic post processor for incompressible, viscous computations. The method is applied to the two-dimensional problem of grazing flow past a cavity. A research RANS code is used to obtain the incompressible flow field quantities. Subsequently, the acoustic calculation is performed using a second-order finite-difference scheme. The method is shown to be a viable strategy for obtaining predictions for the acoustic field associated with a viscous, subsonic flow.

On Detached Shocks for Blunt Bodies at Small Angles of Attack

1965 ◽  
Vol 32 (2) ◽  
pp. 271-276
Author(s):  
Hsuan Yeh ◽  
Raymond Doby
Keyword(s):  
Flow Field ◽  
Rigid Body ◽  
Blunt Body ◽  
Subsonic Flow ◽  
The Body ◽  
Body Rotation ◽  
Numerical Computations ◽  
Primary Flow ◽  
Perturbation Procedure ◽  
Blunt Bodies

This paper is addressed to the problem of determining the subsonic flow field that exists between the shock and the associated blunt body at small angles of attack. An inverse perturbation procedure is used whereby the shock itself is caused to rotate and the body that supports the perturbed shock is determined. It is found that the perturbed body does not possess a rigid-body-rotation relation relative to the primary flow body. Curves and tables are presented which represent the results of the numerical computations.

Singular Cell Adaptive Method for Adaptively Refined Cartesian Grid in the Simulation of Flow around Airfoil

2013 ◽  
Vol 275-277 ◽  
pp. 537-542
Author(s):  
Yu Qi Han ◽  
Lin Gao ◽  
Ge Gao
Keyword(s):  
Flow Field ◽  
Transonic Flow ◽  
Subsonic Flow ◽  
Solid Wall ◽  
Adaptive Method ◽  
Current Approach ◽  
Cartesian Grid ◽  
Time Step ◽  
Cut Cell ◽  
Volume Method

A novel adaptive method for singular geometric regions was proposed. Combined with conventional cut cell adaption, curvature cell adaption and solution adaption, adaptively refined Cartesian grid was automatically generated after geometries had been specified by users. Solid wall boundary was implemented by ghost body-cell method which efficiently relieved the time step restriction of small cut cells. Flow field was well resolved on adaptively refined Cartesian grid with finite volume method. Transonic flow around the RAE2822 airfoil and subsonic flow around the Suddhoo four-element airfoil are carefully investigated, which validate the efficiency of current approach and its feasibility in complicated geometric regions.

Generation of axi-symmetric body shapes in subsonic flow by means of polynomial distributions of sources and doublets along the axis of symmetry

1987 ◽  
Vol 91 (904) ◽  
pp. 155-169 ◽  
Author(s):  
P. A. T. Christopher ◽  
C. T. Shaw
Keyword(s):  
Flow Field ◽  
Subsonic Flow ◽  
Discrete Source ◽  
Typical Case ◽  
Storage Requirement ◽  
Bodies Of Revolution ◽  
Panel Methods ◽  
Computer Storage ◽  
Axis Of Symmetry ◽  
Body Shapes

Summary A method is presented for determining the potential flow around bodies of revolution, at incidence, in uniform, incompressible, flow. This method utilises polynomial distributions of both sources and doublets, in the manner of Fuhrmann, and gives considerable advantage over existing techniques. In particular, when compared with the method of Nielsen, in a typical case, the computer storage requirement is reduced by a factor of eleven. Compared with panel methods the saving is very much greater. Unlike the method of Landweber, both body surface and flow field conditions are obtainable and it would appear that the new method is ideally suited to the ‘store trajectory’ application in place of the existing discrete source method.

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