Hi.

Sorry for the non-CFD question, but I guess that the subject is enough fluid mech. to make it ok.

I am looking for at 5-hole (or 7-hole, or 8, 9, 10 etc.) pitot probe to measure velocity as well as direction. But I cannot find anyone to sell me one. Do you guys know of any producers?

examples, http://www.dantecmt.dk/Pressureprobes/Index.html http://www.unitedsensorcorp.com/3d.html

Thank you.

The Dantec (aeroprobe) pitot I knew. Are there any other producers.

The dantec probe has a lower limit of 5m/s and the united sensor probe of approx. 1.2m/s

Do you know why there are this difference. Can it be because the probe-hole size is different and that the Barker effect is the restriction limit?

Or can it be that the dantec probe has larger demands to the accuracy?

5 m/s? do you mean like 0.5 m/s maybe?

My guess is that when the velocity gets too low, it becomes harder to measure the difference between pitot pressure and the static/surface pressure on the cone surface. The velocity resolution should have something to do with that.

Barker effect might play a role since pressure probes have issues if the Reynolcs number associated with the flow around the probe becomes too low. BUt if you are able to measure the pressure differnces in the calibration process, Barker effect should not be an issue. Barker effect is hard to quantify in the normal calibration process anyway since the usual practice is to calibrate probes in a uniform, not a shear flow near the wall. For the true answers, you might want to look up the aeroprobe literature. There is a bunch of papers on their probes in AIAA.

But basically, you can also take five tubes, chamfer them, bundle them together and make your own five hole probes.