Numerical Investigation of Boundary-layer Transition Initiated by a Wave Packet for a Cone at Mach 6

2010 ◽  
Author(s):  
Jayahar Sivasubramanian ◽  
Hermann Fasel
Keyword(s):  
Boundary Layer ◽  
Wave Packet ◽  
Numerical Investigation ◽  
Boundary Layer Transition ◽  
Layer Transition

Effects of Streamwise Pressure Gradient on Turbulent Spot Development

1996 ◽  
Vol 118 (4) ◽  
pp. 737-743 ◽  
Author(s):  
J. P. Gostelow ◽  
N. Melwani ◽  
G. J. Walker
Keyword(s):  
Boundary Layer ◽  
Wave Packet ◽  
Pressure Distribution ◽  
Boundary Layer Transition ◽  
Variable Pressure ◽  
Pressure Gradients ◽  
Turbulent Spot ◽  
Layer Transition ◽  
Turbulent Layer ◽  
Wide Range

A pressure distribution representative of a controlled diffusion compressor blade suction surface is imposed on a flat plate. Boundary layer transition in this situation is investigated by triggering a wave packet, which evolves into a turbulent spot. The development from wave packet to turbulent spot is observed and the interactions of the turbulent spot with the ongoing natural transition and the ensuing turbulent boundary layer are examined. Under this steeply diffusing pressure distribution, strong amplification of primary instabilities prevails. Breakdown to turbulence is instigated near the centerline and propagates transversely along the wave packet until the turbulent region dominates. An extensive calmed region is present behind the spot, which persists well into the surrounding turbulent layer. Celerities of spot leading and trailing edges are presented, as is the spanwise spreading half-angle. Corresponding measurements for spots under a wide range of imposed pressure gradients are compiled and the present results are compared with those of other authors. Resulting correlations for spot propagation parameters are provided for use in computational modeling of the transition region under variable pressure gradients.

Numerical Investigation on the Second Stator Boundary Layer Under Clocking Effects: Comparison of v2f and LCL-Model

2008 ◽  
Author(s):  
Axel Heidecke ◽  
Bernd Stoffel
Keyword(s):  
Boundary Layer ◽  
Numerical Investigation ◽  
Separation Bubble ◽  
Measurement Data ◽  
Turbulence Models ◽  
Boundary Layer Transition ◽  
Navier Stokes ◽  
Layer Transition ◽  
Numerical Work ◽  
Boundary Layer Development

This paper presents the results of a numerical investigation of a 1.5-stage low pressure turbine. The main focus of the numerical work was the prediction of the stator-2 boundary layer development under the influence of the stator stator clocking. The turbine profile used for the examination is a so called high-lift-profile and was designed for a laminar-turbulent transition over a steady separation bubble. The boundary conditions were defined by the 1.5-stage test turbine located at our laboratory, where also the measurement data was derived from. The calculations were conducted with a two-dimensional Navier-Stokes solver using a finite volume discretisation scheme. The higher level turbulence models v′2-f and the LCL-turbulence model, which are capable to predict boundary layer transition were compared with measurement data at midspan.

scholarly journals Effects of Streamwise Pressure Gradient on Turbulent Spot Development

1995 ◽  
Author(s):  
J. P. Gostelow ◽  
N. Melwani ◽  
G. J. Walker
Keyword(s):  
Boundary Layer ◽  
Wave Packet ◽  
Pressure Distribution ◽  
Boundary Layer Transition ◽  
Variable Pressure ◽  
Pressure Gradients ◽  
Turbulent Spot ◽  
Layer Transition ◽  
Turbulent Layer ◽  
Wide Range

A pressure distribution representative of a controlled diffusion compressor blade suction surface is imposed on a flat plate. Boundary layer transition in this situation is investigated by triggering a wave packet which evolves into a turbulent spot. The development from wave packet to turbulent spot is observed and the interactions of the turbulent spot with the ongoing natural transition aad the ensuing turbulent boundary layer are examined. Under this steeply diffusing pressure distribution strong amplification of primary instabilities prevails. Breakdown to turbulence is instigated near the center line and propagates transversely along the wave packet until the turbulent region dominates. An extensive calmed region is present behind the spot which persists well into the surrounding turbulent layer. Celerities of spot leading and trailing edges are presented, as is the spanwise spreading half-angle. Corresponding measurements for spots under a wide range of imposed pressure gradients are compiled and the present results are compared with those of other authors. Resulting correlations for spot propagation parameters are provided for use in computational modeling of the transition region under variable pressure gradients.

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