Thermoviscous fluid flow modes in a plane nonisothermal layer

Resumo

This paper deals with 3D flow of thermoviscous fluid in the low compressibility approximation within a cubic-shaped domain enclosed between two flat plates with different temperatures. For two other directions, the problem statement assigns periodic boundary conditions, while the steady pressure drop is sustained for the head flow direction. Such formulation allows to trace the evolution of initial disturbances imposed on the main flow depending on perturba-tion properties. In this case, we consider a degenerate one-dimensional divergence-free noise that is modified by a special correlation filter. When the divergent noise is generated, the solenoid nature of random velocity field must be restored. The simulation demonstrates that random disturbance field development leads to two different scenarios: for the first low-amplitude case, the velocity profile loses initial inflection point and its flowrate increases by 1.5–1.6 times, but for the second one, the flow turbulization occurs destroying the flow core and decreasing the flowrate. In both outcomes, the transition to a steady flow mode in terms of either stationary velocity fields or statistical averag-es takes place for a long interval: up to t~200 dimensionless time units. The analysis of simulated flow is based on integral kinetic energy curves and enstrophy and also via spatial averaging of the obtained data arrays.