The streamwise development of Goertler vortices in a favorable pressure gradient

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2836597· OSTI ID:194226

Finnis, M V; Brown, A ^[1]

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1. Cranfield Univ., Shrivenham (United Kingdom)

Measurements are presented of the streamwise velocity variation within a laminar boundary layer on a concave surface of 4 m radius of curvature for which the free-stream velocity gradient factor ({nu}/U{sub 0}{sup 2})dU{sub 0}/dx was approximately 1 {times} 10{sup {minus}6}. The velocity variation was consistent with the presence of counterrotating vortices resulting from the Goertler instability. The vortices exhibited exponential growth over the streamwise extent of the measurements to a disturbance amplitude of approximately 13% of the local free-stream velocity. The vortex growth rates were found to be less than those for a zero velocity gradient factor, indicating that a favorable pressure gradient stabilizes the flow with respect to the Goertler instability. Boundary layer profiles at local upwash and downwash positions are compared with the linear theory for which the mean flow was modeled using the Pohlhausen approximation to the solution of the boundary layer equations. The agreement between the measured and predicted profiles indicates that the linear stability theory can provide a fair approximation to the small amplitude growth of the Goertler instability.

• Sponsoring Organization: USDOE
• OSTI ID: 194226
• Report Number(s): CONF-940626--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 1 Vol. 118; ISSN 0889-504X; ISSN JOTUEI
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
33 ADVANCED PROPULSION SYSTEMS
BOUNDARY LAYERS
GAS TURBINES
PRESSURE GRADIENTS
TURBINE BLADES
VORTICES