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## Graduate School of Science and Engineering

Mechanical Engineering

### Laboratory of Fluid Mechanics, Prof.Hirata

#### Staff

#### Research Contents

The Laboratory of Fluid Mechanics undertakes research, both basic and applied, on the fluid behaviors and properties in various systems, as follows.

<1> Flow-Induced Vibrations

Proposal, development, and investigation of simple new oscillators (identification of oscillation range including low Reynolds number range, oscillation characteristics within the range, critical Reynolds number, etc). Elucidation of mechanisms generating various flow-induced vibrations, such as fluidity oscillators, flip-flop jet nozzle and bluff-body flutter in a uniform flow, identification of their oscillation region and oscillation limits, and research on their applications and control.

Proposal, development, and investigation of simple new oscillators (identification of oscillation range including low Reynolds number range, oscillation characteristics within the range, critical Reynolds number, etc). Elucidation of mechanisms generating various flow-induced vibrations, such as fluidity oscillators, flip-flop jet nozzle and bluff-body flutter in a uniform flow, identification of their oscillation region and oscillation limits, and research on their applications and control.

<2> Flow between Rotating Disks

Various flow phenomena arise near a floppy disk or other rotating disk due to the boundary conditions and the Reynolds number. We are currently conducting research and analysis to clarify the flow between two coaxially rotating disks.

Various flow phenomena arise near a floppy disk or other rotating disk due to the boundary conditions and the Reynolds number. We are currently conducting research and analysis to clarify the flow between two coaxially rotating disks.

<3> Computational Fluid Dynamics

Development and improvement of analysis methods for various hypothesized flow fields, including difference methods, vortex methods, and discrete singularity methods. Verification of the simulated results is performed using the test results and visualization data.

Development and improvement of analysis methods for various hypothesized flow fields, including difference methods, vortex methods, and discrete singularity methods. Verification of the simulated results is performed using the test results and visualization data.

<4> Flow and Heat Transfer in a Cavity

We conduct research on 2D cavity flow with sinusoidal oscillation of the boundary to enhance the efficiency of diffusion and mixing as well as research on the effects of gravitational oscillations on natural convection and research on fluid sloshing as basic research on the promotion of heat dispersion due to forced oscillation of a container.

We conduct research on 2D cavity flow with sinusoidal oscillation of the boundary to enhance the efficiency of diffusion and mixing as well as research on the effects of gravitational oscillations on natural convection and research on fluid sloshing as basic research on the promotion of heat dispersion due to forced oscillation of a container.

<5> Jet Flow and Rotational Flow and Their Applications

As basic research on solid transport, we conduct research on rotational and non-rotational flows in round pipes and near round pipe inlets, research on solid-liquid mutual interactions that are important when suction-lifting solids, and research on annular ejectors that are attracting attention as simple constructions for jet pumps.

As basic research on solid transport, we conduct research on rotational and non-rotational flows in round pipes and near round pipe inlets, research on solid-liquid mutual interactions that are important when suction-lifting solids, and research on annular ejectors that are attracting attention as simple constructions for jet pumps.

<6> Separating Flow

High-Reynolds-number flows and flow-induced vibrations are often characterized by separating flows. The Laboratory of Fluid Mechanics conducts research on flows around two-dimensional bluff bodies and wake vortices behind three-dimensional bluff bodies.

High-Reynolds-number flows and flow-induced vibrations are often characterized by separating flows. The Laboratory of Fluid Mechanics conducts research on flows around two-dimensional bluff bodies and wake vortices behind three-dimensional bluff bodies.

<7> Acoustic Streaming

Steady flows, which appear near an ultrasonic sound source in addition to the sinusoidal oscillations, are known as acoustic streaming or ultrasonic flows. They are expected to find applications in gravity-free spaces. We conduct computational simulations to elucidate these flows near various-shaped sound sources.

Steady flows, which appear near an ultrasonic sound source in addition to the sinusoidal oscillations, are known as acoustic streaming or ultrasonic flows. They are expected to find applications in gravity-free spaces. We conduct computational simulations to elucidate these flows near various-shaped sound sources.

<8> Other research on thermal flow characteristics in fuel cells, automotive catalytic converters, and etc.

#### Keywords

- Fluidic oscillator
- Flow between two rotating disks
- Computational fluid dynamics
- Slow flow
- Ejectors
- Siphon

- Flow-induced vibrations
- Flutter
- Shear layer control
- Acoustic streaming
- Fuel cell
- Automotive catalytic converter