Effects of surface roughness and particulates on heated laminar flow
Abstract
The effects of a range of surface roughness and background particulates on the delayed transition of a thermally stabilized boundary layer in water was studied experimentally using laser Doppler velocimetry. Particles of 12.5 and 35-micron size had no measurable effect on the transition for any of the test conditions of surface roughness or heating. However, the transition was significantly affected by 80 and 133-micron particles. Above a length Reynolds number of 4 x 10 to the 6th, the boundary layer transition location moved forward on the body due to the effec of 80 and 133-micron particles for all heating conditions. The largest percentage changes in the transition location were observed for the smoothest (0.15 micron) surface finish with 80-micron seeding particles. The sensitivity of the transition location to the surface roughness increased with surface heating.
- Publication:
-
Applications of Laser-Doppler Anemometry to Fluid Mechanics
- Pub Date:
- 1982
- Bibcode:
- 1982alaf.symp....2L
- Keywords:
-
- Boundary Layer Transition;
- Laminar Boundary Layer;
- Microparticles;
- Particulates;
- Surface Roughness Effects;
- Thermal Stability;
- Two Phase Flow;
- Flow Measurement;
- Laser Doppler Velocimeters;
- Particle Size Distribution;
- Reynolds Number;
- Sea Water;
- Signal Processing;
- Surface Temperature;
- Temperature Effects;
- Turbulent Boundary Layer;
- Water Flow;
- Fluid Mechanics and Heat Transfer