International Space Science Institute
This presentation is the property of its rightful owner.
Sponsored Links
1 / 26

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


  • 80 Views
  • Uploaded on
  • Presentation posted in: General

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.

Download Presentation

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

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


Flow on the leeward side of a supersonic source in a supersonic stream

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


Flow on the leeward side of a supersonic source in a supersonic stream

  • Unexpected and interesting phenomena can occur on the leeward (night) side of a comet in the solar wind flow. One of these phenomena can be the formation of return (circulatory) flow zones.

  • The results of Dr. Benna’s simulation hint at this possibility


Flow on the leeward side of a supersonic source in a supersonic stream

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)


Flow on the leeward side of a supersonic source in a supersonic stream

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

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


Flow on the leeward side of a supersonic source in a supersonic stream

The similar situation can occur in subsonic flow past a supersonic source


Flow on the leeward side of a supersonic source in a supersonic stream

Reflection of a shock wave from the axis of symmetry in uniform, wake, and source flows


Flow on the leeward side of a supersonic source in a supersonic stream

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.


Flow on the leeward side of a supersonic source in a supersonic stream

Low-pressure jetlet in a supersonic underexpanded jet

1 –nozzle;

2 –jetlet;

3 –shock;

4– recirculation zone

G. F. Glotov, 1994


Flow on the leeward side of a supersonic source in a supersonic stream

B.J. Gribben, K.J. Badcock, B.E. Richards. 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


Flow on the leeward side of a supersonic source in a supersonic stream

Numerical experiment by M. Frey


Flow on the leeward side of a supersonic source in a supersonic stream

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


Flow on the leeward side of a supersonic source in a supersonic stream

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).


Flow on the leeward side of a supersonic source in a supersonic stream

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

Numerical calculation (streamlines)

Glotov’s experiment


Flow on the leeward side of a supersonic source in a supersonic stream

Density c ontours for the above calculation


Flow on the leeward side of a supersonic source in a supersonic stream

The problem of supersonic spherical source flow in a cylindrical channel


Calculated flow pattern at gamma 1 4

Calculated flow pattern at gamma = 1.4

Calculated flow pattern atgamma = 1.05


Calculations by the aav method

Calculations by the AAV method


Flow on the leeward side of a supersonic source in a supersonic stream

Source flow with nonuniform angular velocity distribution (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.


Flow on the leeward side of a supersonic source in a supersonic stream

THANK YOU


  • Login