# Creating controlled cavitation underwater (bubbles)

• fishflyguy
In summary, the speaker is wondering if they can create cavitation underwater with a specific venturi device, operating at varying depths and temperatures in saltwater. They have done some calculations and are wondering if they can consistently create bubbles without causing damage, possibly for a sea fishing application.
fishflyguy
Hello all- First post.

I am curious if it is possible to create cavitation underwater with these specific criteria. I am basically using a venturi device that will be pulled underwater in saltwater. Is it possible to get the vapor pressure down low enough to boil water (make bubbles).

I have done some rudimentary calculations and I got some Reynolds number in the 132,000 range which would be quite turbulent flow.

Here are the parameters of my question:

Venturi inlet diameter is .7500 inches (cannot change this...hopefully)
Venturi throat is .0937 inches (3/32) in diameter. (this can diameter can change)
The total length of venturi device is 1" 3/8"
The Venturi will be operated at depths of 10 feet to 50 feet below the surface of salt water
The Venturi will be operated in salt water with a temperature of 5 degrees C to 20 degrees C
The Venturi device will be moving from 2-5 knots consistently underwater.
3 knots is 1.543 meters/ second
Venturi will be made of yellow brass.
Optimum bubble diameter would be between 1/8" to 1/4"

My two questions are:
1. can I make consistent bubbles underwater?
2. Specifically can I make NON-destructive cavitating bubbles with the above criteria?

Cavitation , turbulence and simple bubble formation are really different things

With set up described I doubt whether you would get any noticeable effect at all .

To deliberately create cavitation you would need to use something like a badly designed powered propeller in a duct .

To create bubbles in a more practical manner the easiest way would be bring down an air line from the surface .

Is all this for a sea fishing application ??

could be i suppose

## 1. What is controlled cavitation underwater?

Controlled cavitation underwater refers to the intentional creation and manipulation of bubbles in a liquid medium by external forces, such as sound waves or mechanical vibrations. This process can be used for various purposes, such as cleaning, mixing, and removing impurities from liquids.

## 2. How is controlled cavitation underwater created?

Controlled cavitation underwater is created by inducing high-frequency sound waves or mechanical vibrations into a liquid medium. This causes the formation of small bubbles, which grow in size until they reach a certain threshold and then collapse, creating a shockwave that can be harnessed for various applications.

## 3. What are the applications of controlled cavitation underwater?

Controlled cavitation underwater has many applications, including cleaning and disinfection of water and wastewater, mixing of chemicals and ingredients, extraction of oils and minerals from liquids, and removal of biofilms and fouling from surfaces. It is also being studied for potential use in medical treatments and drug delivery methods.

## 4. What are the benefits of using controlled cavitation underwater?

The use of controlled cavitation underwater offers several benefits, such as efficient and cost-effective cleaning and mixing processes, reduced chemical and energy consumption, and minimal environmental impact. It can also be used in areas where traditional methods are not feasible, such as underwater or in confined spaces.

## 5. Are there any potential risks associated with controlled cavitation underwater?

While controlled cavitation underwater has many benefits, there are also potential risks to consider. These include damage to sensitive equipment or structures due to the shockwaves created by collapsing bubbles, as well as potential harm to aquatic life if not properly controlled. Therefore, it is essential to carefully plan and monitor the use of controlled cavitation underwater to mitigate any potential risks.

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