Oblique and expansion waves?

In summary, the conversation revolves around the topic of oblique shock waves and expansion waves. The person asking for help is working on a research project for Year 12 and needs evidence of seeking help from others. They explain their understanding of oblique shock waves and how they can increase drag on an aircraft. Another person suggests looking into wave drag for more information. Overall, the conversation is focused on understanding these types of shock waves and their effects on aircraft.
  • #1
fatlady1ac
17
0
Would anybody be able to give me a simple definition on the question below.
Thanks Dylan

 What are oblique shock waves? What are expansion waves?
 
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  • #2
This smells like homework, in which case we are not allowed to answer without you following the guidelines outlined in the homework section and showing that you have at least attempted the problem. Honestly, assuming this is homework, you can find this pretty quickly in your textbook... or on Google.
 
  • #3
Its not necessarily homework, however I understand the guide rules, but I agree why it cannot be answered. It is actually a research project which I have to finish as part of my Year 12 which is anoyingly tedious. Anyway I need to have shown evidence that I have asked others for help, and the various people I have tried to talk to in the industry have not replied. Thus I thought I could ask a few questions on PF as part of my communication.
Thanks for the reply anyway I appreciate it.
 
  • #4
Do you have a compressible flow book handy like Anderson or Oosthuizen (sp)?
 
  • #5
a quick google or wiki search will tell you everything you need to know for casual research on the subject.
 
  • #6
Yes I have a book written by John D. Anderson called Fundamentals of Aerodynamics.
From what I have studied is right to assume that a shock wave that occurs at a given angle to the flow is an oblique shock wave, and the fluid in the shock increases in density as it is compressed, resuting in greater pressure and temperature. So the fluid flow speed downstream is less.
Does the above directly increase the drag on an aircraft by converting some of the propulsive (kinetic energy) to thermal energy.
My research is directed into how to the speed of sound increases drag.
Thanks
 
  • #7
Google wave drag. That ought to give you a little help.
 
  • #8
Thanks for all the replies, I have subsequently looked at wave drag and it has been of help.
 

1. What are oblique and expansion waves?

Oblique and expansion waves are two types of shock waves that occur when a fluid or gas is suddenly compressed or expanded. Oblique waves occur when the compression or expansion is at an angle to the direction of the flow, while expansion waves occur when the compression or expansion is perpendicular to the flow.

2. How do oblique and expansion waves form?

Oblique and expansion waves form as a result of the sudden change in pressure and velocity of a fluid or gas. This can be caused by various factors such as an object moving through the fluid or a sudden change in the environment.

3. What is the difference between oblique and expansion waves?

The main difference between oblique and expansion waves is the direction of the compression or expansion in relation to the flow. Oblique waves occur at an angle to the flow, while expansion waves occur perpendicular to the flow. Additionally, the shock front of an oblique wave is curved, while the shock front of an expansion wave is straight.

4. How do oblique and expansion waves affect the surrounding environment?

Oblique and expansion waves can have significant effects on the surrounding environment, depending on the intensity and duration of the shock wave. These effects can include changes in pressure, temperature, and flow velocity, which can impact nearby objects and structures.

5. Can oblique and expansion waves be controlled or mitigated?

Yes, oblique and expansion waves can be controlled or mitigated through various methods such as the use of shock-absorbing materials, altering the shape or design of objects, or using shockwave cancellation techniques. However, the effectiveness of these methods may vary depending on the specific situation and intensity of the shock wave.

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