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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

EFFECTS OF TRANSVERSE OSCIILATORY WAVES ON TURBULENT BOUNDARY LAYERS

Get access (open in a dialog) DOI: 10.1615/IHTC10.1080
pages 65-70

Аннотация

Many flow fields are characterized by velocities with time-dependent oscillating components. Rocket motors, for example, exhibit instabilities which can lead to longitudinal, circumferential, and radial oscillations in pressure and velocity. Such oscillations in the flow field can and have led to the loss of the motor due to excessive wall heat transfer. Since it has been shown that early transition to turbulence for such flows is generally not sufficient to cause motor failure, a probable cause is the increase in heat transfer due to a coupling between the turbulent and periodic oscillations.
The instabilities found in solid rocket motors are primarily longitudinal in nature and usually occur at low frequencies. This tends to decrease the severity of the turbulent oscillatory coupling. Liquid rocket motors, however, are subject primarily to transverse oscillatory modes (i.e. circumferential and radial) which occur at higher frequencies, and make the problem a transient three-dimensional one.
In the present paper, the effects of transverse oscillatory waves are examined. A turbulent boundary layer with a uniform axial flow is subjected to a transverse velocity oscillation from 0 to 1000 rad/sec and amplitude of 0 to 75% of the axial free stream velocity. These amplitudes are consistent with those associated with liquid rocket motor potential instabilities; although, the frequencies in rocket motors are typically often higher.