Reactive control of velocity fluctuations using an active deformable surface and real-time PIV

• Author / Creator

  McCormick, Findlay

• This work investigated the use of an active deformable surface and real-time particle image velocimetry (RT-PIV) for reactive control of periodic vortex shedding from a wall-mounted spherical cap immersed in a laminar boundary layer. The reactive control strategies involved locally targeting wall-normal (v) or streamwise (u) velocity fluctuations with velocity fluctuations induced by wall-normal surface deformations that comply with or oppose the measured velocity fluctuations. These strategies were inspired by similar ones that were numerically investigated by Choi et al. (1994). Our investigation found that the reactive control strategies generally inhibited the penetration of sweep motions towards the wall. Among the investigated strategies, those employing opposing v-control and compliant u-control demonstrated the greatest inhibition of sweep motions. As well, the reactive control strategies caused significant disruption of the periodic vortex shedding process with the extent of disruption being related to the amplitude of actuations. The greatest disruption was achieved by v-control applying opposing actuations. The opposing v-control cases applying the strongest actuations reduced the energy of two POD modes associated with vortex shedding by up to 69% relative to the unforced flow. For many of the cases that showed the greatest disruption of the periodic flow, the turbulent kinetic energy (TKE) of the flow was also increased relative to the unforced flow. Opposing actuation cases of v -control and compliant actuation cases of u-control exhibited the lowest TKE values on average. Consequently, these cases of reactive control proved to be the most effective at decreasing the energy of the vortex shedding process with minimal additional energy introduced in the form of other flow motions.

• Subjects / Keywords

  • flow control

• Graduation date

  Fall 2023

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-jvc0-xx19

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.