Hi Dinar,

Your question is interesting, and since nobody is answering, I can try to start the conversation.

What is your wall material and curvature? Refractive index matching can indeed make your life easier for PIV applications. If you want a literature review :Article A review of solid–fluid selection options for optical-based ...

But it may not be absolutely needed for near-wall turbulence: Article Measurement of fully-developed turbulent pipe flow with digi...

And it is common to minimize image distortion due to the wall curvature by using a square box filled with liquid (or designed with reverse circular shape) around the test section.

Article Advection velocities of flow structures estimated from parti...

Article Investigation of particle-laden turbulent pipe flow at high-...

For pipe flows at high Reynolds number, you can check the CICLoPE facility of the University of Bologna (https://www.euhit.org/infras/ciclope/facilities).

This should be the strongest reference for your study with PIV measurements: Article Near-wall statistics of a turbulent pipe flow at shear Reyno...

There is also the Princeton SuperPipe ( http://www.princeton.edu/~gasdyn/Facilities/Facilities.html), but they use hot wire and NSTAP.

Article Turbulence spectra in smooth- and rough-wall pipe flow at ex...

For more pipe flow theory:

Article Spectral scaling in boundary layers and pipes at very high R...

Article Turbulent boundary layer statistics at very high Reynolds number

Article On the universality of inertial energy in the log layer of t...

Good luck with your setup,

Best,

Charles

Your question is interesting

Hi Dinar,

what is a CIRCULAR pipe? Is it a pipe with circular cross section? If yes, then surely the radius and the lenght scale of energy-containing eddies near boundary matter. I am just thinking exactly about this topic and a nice application would be the Princeton superpipe, http://www.princeton.edu/~gasdyn/Facilities/Facilities.html ,

and/or the COLA pipe,

https://www.b-tu.de/fg-aerodynamik-stroemungslehre/forschung/ausstattung/colapipe .

Note also this theory-oriented paper:

Article Universal equations and constants of turbulent motion

If you see a chance for collaborative work, it could be nice. Only some research coins are needed: not for profit. For the honor only ...