School Seminars and Colloquia

PhD Seminar: High speed flows: from water bells to atmospheric entry vehicles


by Ellie Button

Institution: Mathematics and Statistics, University of Melbourne
Date: Tue 23rd March 2010
Time: 12:00 PM
Location: Russell Love Theatre, Richard Berry Bldg, The Uni of Melb

Abstract: The fluid dynamics of high speed flows is discussed in the context of (i) a high Reynolds number flow, and (ii) a high Mach number flow.

(i) The thin film flow generated when a vertical liquid jet impacts on the
underside of a large horizontal plate, spreads radially to an unspecified abrupt
point, and then falls of its own accord. The fluid falls in threads, which may
coalesce to form a water bell. The stability of the thin film flow along the plate is considered as a mechanism
for the fluid's departure from the plate in the case of a water bell, and an
analytical model for the departure radius is developed. This departure radius
is seen to obey a different mechanism in the case of liquid threads;
experimental results are discussed.

(ii) Spacecraft entry into the atmosphere of a planet requires protection against
the extreme temperatures that result from aerodynamic heating. This is
normally achieved through use of a heat shield, which also provides the
necessary aerodynamic braking and stability. The ``blunted-cone'' heat
shield is often employed, and has been developed through experimental design and computational simulation. Here, we demonstrate that this generic shape can be derived mathematically and yields the maximum aerodynamic torque of all possible shapes. The derived single shape is universal, depending only on thecentre-of-mass, and provides invariance in static stability due to minor heat shield damage.

For More Information: Contact Paul Pearce ( or Paul Norbury (

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