Calculating Reflected Pressures in Mach Reflection Region

In summary, calculating reflected pressures in the Mach reflection region involves considering the incident shock wave and reflected shock wave angles, as well as the ratio of specific heats and the Mach number. The reflected pressure can be calculated using the Rankine-Hugoniot relations and can provide insight into the flow behavior in this complex region.
  • #1
lasfoe
1
0
Hello guys,

I want to compute reflected pressures in Mach reflection region. In Mach reflection, let's just think about the reflected, incident and merged pressures (of Mach stem). You know, the merged pressure is created by coalescing the incident and reflected pressures. Assuming that all the pressures are straight lines, can I simply calculate the merged pressure given that the incident and reflected pressures are known at the moment of transition from regular to Mach reflection?

Or is the merged pressure just the sum of the scalar values of two pressures independent of the angle of incidence and reflection? If so, the reflected pressure from the merged pressure will be always larger than the reflected pressure before Mach reflection. But, this might be not true because I have to consider dynamics pressures as well as static pressures. I have difficulties of handling the two different kinds of pressures in the calculation of the merged pressure and the reflected pressure from it after Mach reflection.

Thank you,
Lasfoe
 
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  • #2
I will not pretend to understand what you are asking. I have studied shock stems and how they behaved during the atomic bomb explosions over Hiroshima and Nagasaki. Just maybe these resources will be useful:

The term shock polar is generally used with the graphical representation of the Rankine-Hugoniot equations in either the hodograph plane or the pressure ratio-flow deflection angle plane. The polar itself is the locus of all possible states after an oblique shock.
http://en.wikipedia.org/wiki/Shock_polar

For the behaviour of shock waves traveling normal to the prevailing flow see:
http://en.wikipedia.org/wiki/Rankine-Hugoniot_equation
 

Related to Calculating Reflected Pressures in Mach Reflection Region

1. What is a Mach reflection region?

A Mach reflection region is a phenomenon that occurs when a supersonic flow encounters a solid surface at a certain angle, causing the flow to reflect and form a shock wave pattern. This region is characterized by a series of shock waves and expansion waves, and it is named after the Austrian physicist and philosopher Ernst Mach.

2. How do you calculate reflected pressures in the Mach reflection region?

The calculation of reflected pressures in the Mach reflection region involves using the Rankine-Hugoniot equations, which relate the properties of a fluid before and after a shock wave. These equations take into account factors such as the incident Mach number, angle of incidence, and the properties of the fluid and the solid surface.

3. What factors affect the magnitude of reflected pressures in the Mach reflection region?

The magnitude of reflected pressures in the Mach reflection region depends on several factors, including the incident Mach number, the angle of incidence, and the properties of the fluid and the solid surface. A higher incident Mach number or a larger angle of incidence will result in higher reflected pressures, while a softer or more reflective surface will decrease the magnitude of the reflected pressures.

4. How can reflected pressures in the Mach reflection region be mitigated?

To mitigate the effects of reflected pressures in the Mach reflection region, engineers and scientists can use various methods such as altering the geometry of the solid surface, changing the properties of the fluid, or using deflection devices. These methods can help to reduce the magnitude of the reflected pressures and minimize their impact on the surrounding environment.

5. Why is it important to accurately calculate reflected pressures in the Mach reflection region?

The accurate calculation of reflected pressures in the Mach reflection region is crucial for understanding the behavior of supersonic flows and their interactions with solid surfaces. This information is important for the design and analysis of various engineering systems such as aircraft, rockets, and missiles, as well as for predicting the impact of supersonic flow on structures and the environment.

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