Re: Building a hydrodynamics water tunnel for surface water wheel testing.

In summary, the channel has a flow straightener in the large inlet to reduce turbulence, and then a contracting nozzle to test the flow. It is unclear if the channel is doing well or not, but it sounds like it is.
  • #1
I need to simulate the flow of a river, to do small scale hydrodynamics testing on a partially submerged water wheel / paddle wheel design. The typical water tunnel setup will not work, because we are interested in the flow near the surface. The water wheel is half in the water, and half out. Anyone have any suggestions? I have been trying to use a long open topped gutter and pump the water in one side, and out a drain on the other. But, I get turbulence reflecting backwards because the water is bouncing back before exiting out of the drain port.

How can I get a smooth flow / current, like a river with both air space and a water surface, without using a closed system that is based on water pressure? In my current open topped gutter setup; should I be using an open end hose pushing the water in the proper direction, or should I use a diffused filter? Or will both get reverberation flow regardless? Thanks so much in advance. Appreciate the advice.
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  • #2
This is just an Idea, (As I don't do any hydrodynamics.) but if you had an accumulator tank that the pump filled from the bottom, and the gutter flowed off the smother top.
This might isolate some of the turbulence.
  • #3
I think you need a combination of the Accumulator filled from the bottom as johnbbahm mentioned to get a smooth flow down the channel/gutter, and remove the drain port such that the channel/gutter drains freely into another storage container to eliminate that turbulent backflow condition.

Rinse and repeat.


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  • #4
Thanks guys, and I think that would probably work. The combination of the two ideas. But, we would have needed a much larger pump with an open ended channel.

However, we actually went with a bottom mounted design now because we are deploying in a tidal basin and our generator units will be under tremendous forces. Shortly, we will receive our financing and many qualified engineers will conduct proper testing on our tidal hydro kinetic turbine generators. Thanks again for the efforts! Much appreciated.

- BaNe
  • #5

Very interesting, since I am also developing a free-surface water tunnel aka a channel. My plans are similar to the drawing of Mushinskull, but I will use a horizontal channel. To reduce turbulence, all tunnels have a flow straightener (honeycomb) in a large inlet section, then a contracting nozzle and then the test section.

So, how is your channel doing? Can you tell me some more about it (flow speed, size of the test section,...)? And where do you work?

1. What is a hydrodynamics water tunnel and how does it work?

A hydrodynamics water tunnel is a specialized laboratory setup designed to simulate the flow of water in different conditions. It consists of a long transparent tank filled with water, a pump to generate the flow, and different measurement instruments to collect data. The water flow is controlled by adjusting the pump speed and the tank is equipped with windows for observation and access to the test objects.

2. Why is a water tunnel necessary for surface water wheel testing?

A water tunnel is necessary for surface water wheel testing because it provides a controlled and realistic environment to study the performance of the water wheel. It allows researchers to accurately measure the forces and velocities acting on the wheel, which can then be used to optimize its design and efficiency.

3. What types of data can be collected in a hydrodynamics water tunnel?

A hydrodynamics water tunnel can collect various types of data such as flow velocity, pressure distribution, turbulence, and drag force. It can also measure the performance of the test object, such as the power output of a water wheel, in different flow conditions.

4. How is the flow rate controlled in a water tunnel?

The flow rate in a water tunnel is controlled by adjusting the speed of the pump. The pump can be operated manually or through computer software, allowing for precise control of the flow rate. Additionally, the design of the water tunnel, such as the shape and size of the tank, can also affect the flow rate.

5. What are some potential challenges when building a hydrodynamics water tunnel?

Some potential challenges when building a hydrodynamics water tunnel include the high cost of equipment and materials, the need for specialized knowledge and skills in fluid mechanics and instrumentation, and the potential for leaks or other technical issues. It is also important to carefully design and calibrate the tunnel to ensure accurate and reliable data collection.

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