Subscribe free to our newsletters via your
. Space Travel News .

Competition of the multiple Gortler modes in hypersonic boundary layer flows
by Staff Writers
Beijing, China (SPX) May 05, 2014

This shows the nonlinear development of the Gortler vortices with Ma=1.5, 3.0, 4.5 and 6.0. Image courtesy Science China Press.

The present study illustrates, for the hypersonic flows, through the local and marching analysis, the crossover of the mode W and the mode T at O(1) wavenumber and large Gortler number regime.

In fact, it is at this wavenumber regime that the instability is most likely to occur. The two approaches are expected to deliver similar results and the marching analysis helps to express the details of the crossover and confirm the result of the local analysis.

In fact the study of Gortler instability goes back to the date of the 1940s. Since Gortler's pioneering investigation on the boundary layer instabilities subjected to the negative curvature in 1940 highlighting the existence of the streamwise-oriented counter-rotating vortices, extensive studies have been carried out on this subject especially in the incompressible flows. These vortices are caused by the imbalance between the centrifugal force and the normal pressure gradient near a concave surface and exhibit a quasi-constant spanwise wavelength.

The most distinct difference between the incompressible counterparts is the existence of the trapped-layer mode (mode T) apart from the conventional wall layer mode (mode W) observed in the incompressible cases.

The velocity disturbances of the multiple Gortler modes are given below in Figure 1. It is evident that the mode T has its disturbances detached from the wall. As a result of this, the nonlinear development of Gortler vortices in hypersonic boundary layers shows considerable differences. Figure 2 shows the development of the streamwise velocity contours of the Gortler flow up to a fully saturated states.

The Mach numbers are 1.5, 3.0, 4.5 and 6.0 respectively. The famous mushroom structures (subsonic and moderate supersonic, e.g., Ma=1.5 and 3.0) are replaced by the bell shapes (hypersonic, e.g., Ma=4.5 and 6.0). This is because the mode T is the most dangerous modal shape in such flows.

To conclude, when considering the flow transition induced by the Gortler instability in hypersonic flows, the mode T highlighted in this article must be considered. Also, with appropriate parameters the mode T and mode W have crossovers. This study is a guidance for future studies of the secondary instability of Gortler vortices and flow transition in hypersonic boundary flows.

The readers are also recommended to read the future articles by the authors. Jie Ren and Song Fu, "Competition of the multiple Gortler modes in hypersonic boundary layer flows" SCIENCE CHINA Physics, Mechanics and Astronomy 2014(6), 1178-1193 DOI: 10.1007/s11433-014-5454-9


Related Links
Science China Press
Rocket Science News at Space-Travel.Com

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

New Craft Will Be America's First Space Lifeboat in 40 Years
Kennedy Space Center FL (SPX) May 02, 2014
The next generation of American spacecraft designed to carry people into low-Earth orbit will be required to function as a lifeboat for the International Space Station for up to seven months. This service has not been provided by an American spacecraft since an Apollo command module remained docked to Skylab for about three months from 1973 to '74. Like a lifeboat on a cruise ship, the spa ... read more

Replacing Russian-made rocket engines is not easy

SHERPA launch service deal to deploy 1200 kilo smallsat payloads

Pre-launch processing begins for the O3b Networks satellites

US sanctions against Russia had no effect on International Launch Services

NASA's Curiosity Rover Drills Sandstone Slab on Mars

Mars mission scientist Colin Pillinger dies

Nonprofit says: fire missiles at Mars to dig for signs of life

ISS research shows that hardy little space travelers could colonize Mars

Astrobotic Partners With NASA To Develop Robotic Lunar Landing Capability

John C. Houbolt, Unsung Hero of the Apollo Program, Dies at Age 95

NASA Completes LADEE Mission with Planned Impact on Moon's Surface

Russia plans to get a foothold in the Moon

Dwarf planet 'Biden' identified in an unlikely region of our solar system

Planet X myth debunked

WISE Finds Thousands Of New Stars But No Planet X

New Horizons Reaches the Final 4 AU

Length of Exoplanet Day Measured for First Time

Spitzer and WISE Telescopes Find Close, Cold Neighbor of Sun

Alien planet's rotation speed clocked for first time

Seven Samples from the Solar System's Birth

Competition of the multiple Gortler modes in hypersonic boundary layer flows

New Craft Will Be America's First Space Lifeboat in 40 Years

Space Launch System Structural Test Stands to be Built at Marshall Space Flight Center

ATK Validates MegaFlex Solar Array For NextGen Solar Electric Propulsion Missions

New satellite launch center to conduct joint drill

China issues first assessment on space activities

China launches experimental satellite

Tiangong's New Mission

25-foot asteroid comes within 186,000 miles of Earth

Halley's Comet-linked meteor shower to peak Tuesday morning

Less than a year from its Ceres rendezvous

Asteroids as Seen From Mars; A Curiosity Rover First

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.