International Space Science Institute
Download
1 / 26

FLOW ON THE LEEWARD SIDE OF A SUPERSONIC SOURCE IN A SUPERSONIC STREAM - PowerPoint PPT Presentation


  • 132 Views
  • Uploaded on

International Space Science Institute Team Meeting “Modeling Cometary Environments in the Context of the Heritage of the Giotto Mission to Comet Halley” 19—24 November, 2012. FLOW ON THE LEEWARD SIDE OF A SUPERSONIC SOURCE IN A SUPERSONIC STREAM. M. G. LEBEDEV.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' FLOW ON THE LEEWARD SIDE OF A SUPERSONIC SOURCE IN A SUPERSONIC STREAM' - leila-johnson


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

International Space Science Institute

Team Meeting “Modeling Cometary Environments in the Context of the Heritage of the Giotto Mission to Comet Halley”

19—24 November, 2012

FLOW ON THE LEEWARD SIDE OF A SUPERSONIC SOURCE IN A SUPERSONIC STREAM

M. G. LEBEDEV



Calculation of supersonic flow past a supersonic source (windward side)

Formulation of the problem in the tail flow region

Calculation using the Babenko—Rusanov method (1980)


Calculation of the flow on the leeward side using the Godunov method

.

General flow pattern

Streamlines

Velocity profile along the axis of symmetry

Longitudinal velocity and pressure distributions in the X = 39 section


Calculated results
Calculated results Godunov method

Density contours

Pressure contours

Longitudinal velocity contours

Vertical velocity contours


Another time dependent formulation of the same problem with the formation of the return flow zones
Another (time-dependent) formulation of the same problem with the formation of the return-flow zones




Formation of return flow zones on reflection of an incident shock from the axis of symmetry in a wake-type flow

1– nozzle;

2 – flame stabilizer

3 – thermal wake from combustion

4 – shock wave

5 –recirculation zone

Hydrogen burns behind a cylindrical stabilizer,G.Winterfeld,1968.


Low-pressure jetlet in a supersonic underexpanded jet shock from the axis of symmetry in a wake-type flow

1 –nozzle;

2 –jetlet;

3 –shock;

4– recirculation zone

G. F. Glotov, 1994


B.J. Gribben, K.J. Badcock, B.E. Richards. shock from the axis of symmetry in a wake-type flow Numerical study of shock-reflection hysteresis in an underexpanded jet // AIAA Journal. 2000. V. 38. N. 2. P. 275—283.M. Frey. Behandlung von Strömungsproblem in Racketendüsen bei Überexpansion // Inst. für Aerodynamik und Gasdynamik, Univ. Stuttgart. Dr.-Ing. Diss. 2001. (http://elib.uni-stuttgart.de/opus/volltexte/2001/800/pdf/diss_frey.pdf)В.А. Горяйнов. О возможности реверса течения в свободных сверхзвуковых струях // Мат. моделирование. 2003. Т. 15. № 7. С. 86—92.О.В. Бочарова, М.Г. Лебедев, А.В. Савин, Е.И. Соколов. Стационарные циркуляционные зоны в сверхзвуковых неравномерных потоках // XXI Школа-семинар ЦАГИ «Аэродинамика летательных аппаратов». Тезисы докладов М.: Изд. ЦАГИ. 2010. С. ??--??.

The existence of these experimentally observed structures was confirmed in numerical calculations.

So far, in the case of the source-type nonuniformity analogous structures were obtained only in numerical experiments


Shock reflection in imperfectly expanded jets
Shock reflection in imperfectly expanded jets shock from the axis of symmetry in a wake-type flow


Numerical experiment by M. Frey shock from the axis of symmetry in a wake-type flow


Our calculations of return flow zones in supersonic underexpanded jets (M = 3, n = 3.5)


To confirm these results, recently we calculated some flows with the formation of circulation, or return, or reverse, zones

The following numerical methods were employed

1. Godunov method (first order)

2. Method of adaptive artificial viscosity (second order of accuracy, on irregular, triangular grids)

developed by I.V. Popov and I.V. Fryazinov in Keldysh Institute of Applied Mathematics.

3. Babenko—Rusanov method (shock-fitting technique of the second order of accuracy).


For testing the technique the wake-type flow experimentally studied by Glotov was numerically modeled.

Numerical calculation (streamlines)

Glotov’s experiment


Density c ontours for the above calculation studied by Glotov was numerically modeled.



Calculated flow pattern at gamma 1 4
Calculated flow pattern at gamma = 1.4 cylindrical channel

Calculated flow pattern atgamma = 1.05


Calculations by the aav method
Calculations by the AAV method cylindrical channel


Source flow with nonuniform angular velocity distribution cylindrical channel(a maximum velocity is reached at the channel axis). The initial data correspond to the case of “uniform” source (gamma = 1.1). The return flow zone disappears.


In this case the velocity on the axis is minimum as a result the return flow zone enlarges
In this case the velocity on the axis is minimum. As a result, the return flow zone enlarges.


THANK YOU result, the return flow zone enlarges.


ad