Turbulence - just a phenomenon of cavitation?

In summary, turbulence and cavitation are two separate phenomena. Turbulence is caused by tiny perturbations in a flow, while cavitation is the formation and implosion of bubbles in a liquid due to changes in pressure. Turbulence can occur in both liquids and gases, while cavitation only occurs in liquids. They are not related and have different properties.
  • #1
Loren Booda
3,125
4
Turbulence -- just a phenomenon of cavitation?

Is turbulence exclusively cavitation of a fluid?

Please give me your insight on this idea.
 
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  • #2


No. Turbulence is a completely separate phenomenon from cavitation. Turbulence has to do with tiny perturbations in a flow growing to the point where the flow becomes highly chaotic.
 
  • #3


Just to add in, cavitation has to do with fluids under high force (as in a boat's prop):

WIkipedia.org said:
Cavitation is the formation and then immediate implosion of cavities in a liquid – i.e. small liquid-free zones ("bubbles") – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low.
http://en.wikipedia.org/wiki/Cavitation
 
  • #4


Additionally, cavitation can occur near the face of a high power sonar transducer (transmitter). When the acoustic intensity gets so high that the low-pressure of the wave is strong enough to rip the water apart, it creats tiny bubbles of dissolved gas. Cavitation is "bad" for a sonar system because it creates a huge impedance mismatch between the transducer and the water. Also the imploding bubbles can physically damage the transducer face.

One interesting sidelight: If the conditions are right the cavitation bubbles will emit a picosecond pulse of light, the color depends on the kinds of dissolved gasses. This is called "sonoluminesence".
 
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  • #5


To emphasize what has already been said,

They are different and unrelated phenomena.
In particular you need a flowing fluid to exhibit turbulence, it cannot exist in a fluid with no average velocity.
Turbulence is a property of flow.

Cavitation, on the other hand can, and does, exist in a tank of standing fluid. It is not a property of flow.

edit:

Turbulence can, and does, occur in both liquids and gasses. It can either be a local or global property of the flow.

Cavitation occurs when the local input of energy to the fluid is sufficient to cause phase change from liquid to gas within the body of the fluid. As such it can only occur in liquids.


go well
 
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1. What is turbulence and how is it related to cavitation?

Turbulence is a chaotic flow of a fluid, characterized by irregular and unpredictable changes in velocity and pressure. It is related to cavitation because cavitation refers to the formation and collapse of bubbles in a fluid, which can cause turbulence due to the sudden changes in pressure and flow.

2. What causes cavitation and how does it affect turbulence?

Cavitation is caused by a decrease in pressure in a fluid, which can occur due to high flow velocities, sharp edges, or other factors. When bubbles form and collapse, they create small-scale turbulence in the fluid, which can then affect the larger-scale turbulence in the flow. This can lead to increased drag and energy loss in systems such as pumps and propellers.

3. Can turbulence be reduced by controlling cavitation?

Yes, turbulence can be reduced by controlling cavitation. This can be achieved by designing systems with smoother surfaces and avoiding sharp edges, as well as using flow control techniques or adding cavitation inhibitors to the fluid.

4. Is turbulence always a negative phenomenon in fluid dynamics?

No, turbulence can have both positive and negative effects in fluid dynamics. While it can cause energy loss and damage in systems, it can also enhance mixing and heat transfer, which can be beneficial in certain applications such as combustion engines.

5. How do scientists study and model turbulence and cavitation?

Scientists use various techniques such as computational fluid dynamics (CFD) simulations, experiments, and theoretical models to study and understand turbulence and cavitation. These methods allow for the analysis and prediction of flow behavior, and can help in the development of strategies to control and mitigate their effects.

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