OPTICAL PROBE FOR MEASURING WALL-SHEAR STRESS
Aspects of this disclosure are directed to optical probes for collecting images of a region of interest for determining wall shear stress. The optical probe includes an imager with a line of sight and a light guide configured to steer light from a light source to the region of interest. The optical probe includes an objective configured to focus light reflected off of the region of interest to the line of sight of the imager. The optical probe can include a micro-lens array at the objective. The micro-lens array can focus light from the objective onto the imager. The imager can collect images from the light from the micro-lens array for determining wall shear stress at the region of interest.
1 . An optical probe for determining wall shear stress of a fluid flow at a region of interest at a wall, the optical probe comprising:
an imager with a line of sight;
a light guide configured to steer light from a light source to the region of interest;
an objective configured to focus light reflected from the region of interest; and
a micro-lens array at the objective, the micro-lens array configured to focus light from the objective onto the imager,
wherein the imager is configured to collect images from the light from the micro-lens array to determine wall shear stress at the region of interest.
2 . The optical probe of claim 1 , further comprising an optical insert that receives light from the region of interest and provides the received light to the objective.
3 . The optical probe of claim 2 , further comprising a housing that encloses said imager, said light guide, said objective, said micro-lens array, and said optical insert.
4 . The optical probe of claim 3 , wherein said housing has a distal end that is in direct contact with the fluid, and said optical insert is positioned at least at a portion of the distal end.
5 . The optical probe of claim 4 , wherein the distal end of said housing is flush with an inner surface of the wall and conformal with a curvature of the wall.
6 . The optical probe of claim 1 , wherein the light guide is configured to reflect light from the light source and direct the light to the region of interest without reflecting light of a wavelength from the region of interest.
7 . The optical probe of claim 4 , wherein the light guide comprises at least one of a dichroic mirror, a semi-reflective mirror, or a polarizing beam splitter.
8 . The optical probe of claim 7 , wherein the light guide is configured to direct light from the light source towards the region of interest coaxially with an optical axis of the objective.
9 . The optical probe of claim 7 , wherein the light guide is configured to direct light from the light source towards the region of interest at an angle with respect to an optical axis of the objective.
10 . The optical probe of claim 1 , wherein the optical probe is configured to be recessed within a wall such that no portion of the optical probe projects into the region of interest.
11 . The optical probe of claim 10 , further comprising a mounting system configured to mount the optical probe within the wall, wherein said mounting system forms a fluid-tight seal with the wall.
12 . The optical probe of claim 1 , further comprising an injection apparatus configured to inject a tracer into the region of interest, the light reflecting off of tracer at the region of interest.
13 . The optical probe of claim 1 , wherein the fluid comprises a gas, a liquid, or a combination thereof.
14 - 22 . (canceled)