Publication

Experimental investigation into localized instabilities of mixed Rayleigh-Bénard-Poiseuille convection

Emeric Grandjean
2008
Theses

Abstract

An experimental study of the stability of the Rayleigh-Bénard-Poiseuille flow was performed in a large transverse aspect ratio channel. The onset for the transverse thermo-convective rolls was determined as a function of the Reynolds number for two different fluids (water: Pr = 6.5 and mineral oil: Pr = 450). Then, the system impulse response was studied and a good agreement with theory was found for the convective/absolute instability transition. Finally the response of the system to localized heating was observed and compared with analytical and numerical results by Martinand, Carrière and Monkewitz (2004 & 2006): experimental thermo-convective global modes are found to correspond to the saturated "steep" variety constructed by Pier, Huerre and Chomaz (2001).

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https://infoscience.epfl.ch/entities/publication/7253ce4a-6581-4922-af66-d34b64aa5777

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Emeric Grandjean
2008
Theses

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/7253ce4a-6581-4922-af66-d34b64aa5777

About this result

Related concepts (23)

Impulse response

In signal processing and control theory, the impulse response, or impulse response function (IRF), of a dynamic system is its output when presented with a brief input signal, called an impulse (δ(t)). More generally, an impulse response is the reaction of any dynamic system in response to some external change. In both cases, the impulse response describes the reaction of the system as a function of time (or possibly as a function of some other independent variable that parameterizes the dynamic behavior of the system).

Frequency response

In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of systems, such as audio and control systems, where they simplify mathematical analysis by converting governing differential equations into algebraic equations.

Algebraic variety

Algebraic varieties are the central objects of study in algebraic geometry, a sub-field of mathematics. Classically, an algebraic variety is defined as the set of solutions of a system of polynomial equations over the real or complex numbers. Modern definitions generalize this concept in several different ways, while attempting to preserve the geometric intuition behind the original definition. Conventions regarding the definition of an algebraic variety differ slightly.

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