Dynamic effects in transition from regular to Mach reflection in steady supersonic flows

Area of Science:

• Fluid Dynamics
• Aerodynamics
• Shock Wave Phenomena

Background:

• Investigating unsteady shock reflection transitions is crucial for understanding complex aerodynamic flows.
• Comparing unsteady transitions with steady-state phenomena provides insights into dynamic flow behavior.

Purpose of the Study:

• To analyze the effect of rapid wedge rotation on the transition from regular reflection (RR) to Mach reflection (MR).
• To compare unsteady shock reflection transitions with steady-state transitions.
• To examine the influence of rotation rate and Mach number on flow features.

Main Methods:

• Experimental investigation of shock reflection transitions under rapid wedge rotation.
• Systematic variation of wedge angle, Mach number, and rotation rates.
• Analysis of flow features including Mach stem height, reflection point position, and shock angles.

Main Results:

• Transition lines for different rotation speeds were obtained, analogous to steady-state detachment transition lines.
• The pivot point had a minor effect on the transition point but significantly influenced Mach stem growth and reflection point movement, especially at higher Mach numbers.
• The transition location was dependent on the pivot point and rotation rate.

Conclusions:

• Rapid wedge rotation introduces distinct unsteady shock reflection dynamics compared to steady states.
• Mach stem growth and reflection point dynamics are sensitive to rotation rate and pivot point, particularly at high Mach numbers.
• Understanding these dynamic effects is essential for predicting shock wave behavior in high-speed applications.