Benrazar

It all depends on results from data collection, but people who have worked on the tunnel far longer than me do not believe they are surface waves. The flow is slow, 15 mm/s, so no possibly prevalent surface waves are observable. Should have said this before, but the fluctuations we are seeing are ~.2 cycles per second. I believe this means that we have relatively short wave height and wavelength, long period waves. According to articles on wave absorbers, wavelength and period seem to be the most important characteristics to design around. Thanks again for your time and input

We are viewing from one side with cameras, and a laser plane with a traverse is projected from underneath the test section for PIV. The water is "seeded" with particles which are then illuminated by the laser plane. Two cameras take pictures at different times and angles which provides the data to build a velocity field of the volume containing the test model. On the form of the tunnel, yeah it is quite short and squashed compared to other ones. I believe we had someone design it specifically for the space we had, but obviously designed it poorly. On the plates, they will be vertical and normal to the flow direction or slightly inclined, all based on articles investigating wave absorbers. In the diagram I drew, I did not include some flow straighteners and plumbing for simplicity, but vortices in the vertical axis could be a source of disturbance. Thanks for that observation.

As an update, pending data collection of the characteristics of the disturbing waves, we will most likely be going with a porous plate design. Anybody have experience with using them as wave absorbers?

Thanks for the leads on those papers. I haven't thought of doing a reference search, thanks for the tip. My knowledge of cfd or similar software is very limited, but if given the opportunity I will try to have a simulation conducted. Thanks for your input. Sorry, I tried to find some photos but didn't have anything good. here's a sketch.

A water tunnel in the lab I work in was designed poorly, and will require the implementation of some sort of wave absorber to eliminate waves disturbing the test section. The tunnel has a very short diverging section (downstream of test section) and afterwards redirects the flow 90 degrees downwards with a vertical wall. The tunnel is used for flow visualization and Particle Image Velocimetry. Has anyone dealt with a similar or relevant issue? Does anyone know of some resources I can look at? Where would you look to find literature or examples on this issue? Thank you -Ben