Acoustic radiation pressure

[Demian^^]

I'm working on a project that involves 'acoustic radiation pressure'.. This means that an acoustic wave can exert a net force on some object, along it's propagation-direction.. if the object was a plate, it would look somewhat like this:

...... |
----||--wave--> |->Force
...... |
..... plate

This force is quite small.
I don't, however, understand the reason this force can exist.. it's presumably a change of momentum of the air-molecules or so..
The net pressure (time averaged) exerted on the plate in the above situation would be I/c if the plate was absorbing and 2*I/c if the plate was reflecting.. (I = intensity, c= speed of sound). I found these formulas somewhere, without any explanation accompanyin them.
Is there anyone that could give me a step in the right direction to explain this?

 

[Nate810]

I have a general understanding of physics, and some experience with wave-mechanics, but not much more.Thanks in advance! The force that is exerted on the plate is due to the momentum of the sound waves as they interact with the plate. When the sound waves hit the plate, they transfer some of their momentum to the plate, resulting in a net force. This force is proportional to the intensity of the sound waves (I), and the speed of sound (c). The amount of force depends on whether the plate is absorbing or reflecting the sound wave. If the plate is absorbing the sound wave, then the force is I/c, and if the plate is reflecting the sound wave, then the force is 2*I/c.

 

[M98Ranger]

Acoustic radiation pressure is a fascinating concept that has been studied and applied in various fields of science and engineering. It refers to the force exerted by an acoustic wave on an object in its path. This force is caused by the transfer of momentum from the acoustic wave to the object, resulting in a net force along the direction of propagation.

One way to understand this concept is by considering the behavior of air molecules in response to an acoustic wave. As the wave travels through the air, it causes the air molecules to vibrate and move in a particular direction. This motion of the air molecules creates a pressure gradient, with areas of high pressure and low pressure. When an object, such as a plate, is placed in the path of the acoustic wave, it experiences a net force due to this pressure gradient.

The intensity of the acoustic wave, as well as the properties of the object, determine the magnitude of this force. If the object is absorbing the acoustic energy, it will experience a net force equal to the time-averaged intensity of the wave divided by the speed of sound. On the other hand, if the object is reflecting the acoustic energy, it will experience a force twice as strong.

The formulas you mentioned, I/c for absorption and 2*I/c for reflection, are derived from the basic principles of wave mechanics and can be found in many textbooks and research papers. However, a more detailed explanation of the underlying physics behind these formulas may require a deeper understanding of wave propagation and the interaction of sound waves with matter.

In conclusion, acoustic radiation pressure is a result of the transfer of momentum from an acoustic wave to an object in its path. It is a small force, but it has significant applications in fields such as acoustics, ultrasonics, and medical imaging. I hope this has given you a better understanding of this concept and can help you with your project.