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Noise induced effects in the axisymmetric spherical Couette flow
O Krivonosova1, M Gritsevich2,3, D Zhilenko1
1Institute of Mechanics, Lomonosov Moscow state University, 119192 Moscow, Russia.
Summary
Noise significantly impacts fluid dynamics, influencing mean flow generation and energy amplification in spherical Couette flow. This study explores these effects using simulations and experiments, revealing insights into flow instabilities and energy dynamics.
Area of Science:
- Fluid dynamics
- Nonlinear dynamics
- Experimental fluid mechanics
Background:
- Most natural flows are subject to random fluctuations (noise).
- Spherical Couette flow is a fundamental system for studying fluid instabilities.
- Understanding noise effects is crucial for modeling real-world fluid phenomena.
Purpose of the Study:
- To investigate the influence of additive noise on axisymmetric, wide-gap spherical Couette flow.
- To analyze mean flow generation and kinetic energy amplification under noisy conditions.
- To explore the impact of noise on flow stability and critical parameters.
Main Methods:
- Numerical simulations of viscous incompressible fluid flow.
- Experimental validation using laser Doppler anemometry.
- Linear stability analysis to determine onset of instabilities.
Main Results:
- Additive noise induces mean flow generation.
- Meridional kinetic energy can be amplified more than azimuthal kinetic energy under certain conditions.
- Noise decreases the critical Reynolds number for flow instability.
- A local minimum in mean flow generation near the critical Reynolds number was observed.
Conclusions:
- Noise plays a critical role in shaping the dynamics of spherical Couette flow.
- The study provides a model explaining meridional kinetic energy growth.
- Findings offer insights into flow behavior relevant to natural and engineered systems.
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