Flow Oscillating Characteristics of Fluidic Oscillator Pairs Using the Interbridge Method

The evolution process and turbulence properties of a transversely oscillating flow induced by a fluidic oscillator are studied in a gravity-driven water tunnel. A planar jet is guided to impinge a specially designed crescent surface of a target blockage that is enclosed in a cavity of a fluidic oscillator. The geometric configuration of the cavity transforms the inherent stability characteristics of the jet from convective instability to absolute instability, so that the jet precedes the persistent back and forth swinging in the cavity. The swinging jet is subsequently directed through two passages and issued alternatively out of the fluidic oscillator. Two short plates are installed near the exits of the alternatively issuing pulsatile jets to deflect the jets toward the central axis. The deflected jets impinge with each other and form a pair of counter-rotating vortices in the near wake of the oscillator with a stagnation point at the impingement point. The stagnation point of the counter-rotating vortex pair moves back and forth transversely because of the phase difference existing between the two issued jets. The merged flow evolving from the counter-rotating vortices formed by the impingement of the two pulsatile jets therefore presents complex behavior of transverse oscillation. The topological models corresponding to the flow evolution are constructed to illustrate the oscillation process of the oscillating flow. Significant momentum dispersion and large turbulence intensity are induced by the transverse oscillation of the merged flow. The statistical turbulence properties show that the Lagrangian integral time and length scales of the turbulence eddies (the fine-scale structure) produced in the oscillating flow are drastically reduced.

Download Full-text

Active Combustion Control Using a Fluidic Oscillator for Asymmetric Fuel Flow Modulation

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit ◽

10.2514/6.2008-4956 ◽

2008 ◽

Cited By ~ 15

Author(s):

Daniel Guyot ◽

Bernhard Bobusch ◽

Christian Oliver Paschereit ◽

Surya Raghu

Keyword(s):

Combustion Control ◽

Fluidic Oscillator ◽

Flow Modulation ◽

Fuel Flow ◽

Active Combustion Control

Download Full-text

Influence of Geometry on a Feedback-Free Fluidic Oscillator with Nonoutlet Facing Jets

AIAA Journal ◽

10.2514/1.j057173 ◽

2018 ◽

Vol 56 (12) ◽

pp. 4768-4774

Author(s):

Frieder Reichenzer ◽

Mike Schneider ◽

Stefan Dörr

Keyword(s):

Fluidic Oscillator

Download Full-text

NUMERICAL MODELLING OF OSCILLATING FLOW FOR ENERGY HARVESTING

MM Science Journal ◽

10.17973/mmsj.2021_12_2021102 ◽

2021 ◽

Vol 2021 (6) ◽

pp. 5360-5365

Author(s):

TOMAS BLEJCHAR ◽

◽

SYLVA DRABKOVA ◽

VACLAV JANUS ◽

◽

...

Keyword(s):

Flow Rate ◽

Volume Flow Rate ◽

Electrical Energy ◽

Maximum Energy ◽

Oscillating Flow ◽

Cfd Simulations ◽

Fluidic Oscillator ◽

Microelectronic Devices ◽

Piezoelectric Elements ◽

New Generation

The energy efficiency of systems, equipment, and sensors is nowadays intensively studied. The new generation of microelectronic sensors is very sophisticated and the energy consumption is in the microwatts range. The energy to power the microelectronic devices can be harvested from oscillating flow in small size channels and so replaceable batteries could be eliminated. Piezoelectric elements can convert energy from oscillation to electrical energy. This paper focuses on the simulation of periodic flow in the fluidic oscillator. CFD simulations were performed for several values of the flow rate. Experimental measurement was carried out under the same conditions as the CFD experiment. The main monitored and evaluated parameters were volume flow rate and pressure loss. Fluid oscillations were analysed based on CFD simulations and the theoretical maximum energy available for the deformation of piezoelectric elements and transformable into electrical energy was evaluated.

Download Full-text