Thermoacoustic waves along the critical isochore

Area of Science:

• Thermodynamics
• Acoustics
• Fluid Dynamics

Background:

• Thermal disturbances near the liquid-gas critical point can generate acoustic emissions.
• Understanding thermoacoustic behavior is crucial for predicting phenomena in critical systems.

Purpose of the Study:

• To investigate acoustic emissions under linear and nonlinear temperature perturbations near the critical point.
• To analyze the influence of reduced temperature (ɛ) on thermoacoustic wave patterns.
• To compare the long-term energy yield of adiabatic processes under different perturbation types.

Main Methods:

• Numerical solution of governing equations for thermoacoustic behavior.
• Simulation of acoustic emission across four decades of reduced temperatures (ɛ).
• Analysis of wave patterns and energy yields under linear and nonlinear temperature perturbations.

Main Results:

• A homogeneous thermoacoustic wave pattern dominates under linear temperature perturbations, largely independent of reduced temperature (ɛ).
• Nonlinear temperature perturbations lead to significant wavefront deformation, strongly dependent on the reduced temperature (ɛ).
• The strong nonlinear effect is transient, with both linear and nonlinear cases converging in energy yield over time.

Conclusions:

• Thermoacoustic behavior near the critical point is highly sensitive to the nature of temperature perturbations.
• Nonlinear effects, though severe, are temporary and do not alter the ultimate energy balance of the adiabatic process.
• The study provides insights into the complex interplay between thermodynamics, acoustics, and fluid dynamics near critical points.