Effects of Sweeping Jet Actuator Parameters on Flow Separation Control.

A parametric experimental study was performed with sweeping jet actuators (fluidic oscillators) to determine their effectiveness in controlling flow separation on an adverse pressure gradient ramp. Actuator parameters that were investigated include blowing coefficients, operation mode, pitch and spreading angles, streamwise location, and size. Surface pressure measurements and surface oilflow visualization were used to characterize the effects of these parameters on the actuator performance.

Negative dielectrophoretic capture of bacterial spores in food matrices.

A microfluidic device with planar square electrodes is developed for capturing particles from high conductivity media using negative dielectrophoresis (n-DEP). Specifically, Bacillus subtilis and Clostridium sporogenes spores, and polystyrene particles are tested in NaCl solution (0.05 and 0.

Acoustophoresis in shallow microchannels.

Acoustophoretic (AP) motion of spherical polystyrene particles in a steady pressure driven flow is investigated in shallow microchannels, where the channel height is comparable to the particle diameter. Particle trajectories at different ultrasonic actuation amplitudes are extracted by a particle tracking algorithm. Depths of the particles are predicted using the streamwise particle speed that is due to the pressure driven flow.

Particle trapping in high-conductivity media with electrothermally enhanced negative dielectrophoresis.

We demonstrate negative dielectrophoresis (DEP) trapping of particles from high-conductivity media using a novel planar microelectrode that allows electrothermal enhancement of DEP traps. DEP force and electrothermal flow motion are investigated using a scaling analysis, numerical simulations, and experiments. Results show that the DEP trapping is enhanced by lateral transport of particles toward the capture zones due to electrothermal flow, whereas DEP trapping occurred only in limited spatial ranges without the flow motion.