Donghyuk KANG
YOU?
Author Swipe
View article: Self-induced vibration of impinging synthetic jets
Self-induced vibration of impinging synthetic jets Open
While numerous studies have examined self-induced vibrations in jets, the focus has predominantly been on continuous jets. Reports on self-induced vibrations in synthetic jets, which are characterized by their excited-vibration frequencies…
View article: Flow deflection characteristics of two-dimensional synthetic jets generated from asymmetric stepped slots
Flow deflection characteristics of two-dimensional synthetic jets generated from asymmetric stepped slots Open
This study examines the behavior of two-dimensional synthetic jets generated from asymmetric stepped slots, focusing on the formation of recirculation regions and jet deflection near the slot. The effects of step length and frequency on th…
View article: Jet Direction Control Using Active Switching Nozzle
Jet Direction Control Using Active Switching Nozzle Open
Many studies have been conducted on fluidic thrust vectoring, which uses a secondary flow to deflect a primary jet, instead of mechanical thrust vectoring including a variable exhaust nozzle, to improve maneuverability and maintainability …
View article: Investigation of Internal Flow near Return Guide Vane Using Jet and Suction Flow
Investigation of Internal Flow near Return Guide Vane Using Jet and Suction Flow Open
The Performance and efficiency of multistage centrifugal compressors, which are required to operate continuously over a long time, are expected to further improve in the future.Many studies have been conducted to optimize the design of var…
View article: Unified Performance Model for S-Shaped Characteristics of Pump-Turbines Considering Reverse Flow
Unified Performance Model for S-Shaped Characteristics of Pump-Turbines Considering Reverse Flow Open
This study proposes a new unified performance model for the S-shaped characteristics of pump–turbines considering reverse flow. The turbine and reverse pump characteristic equations were unified using a sigmoid function considering the rev…
View article: Stability Analysis of Cavitation Surge in Hydraulic System Considering Response Delay of Cavitating Pump
Stability Analysis of Cavitation Surge in Hydraulic System Considering Response Delay of Cavitating Pump Open
Cavitation surge is a system instability caused by mutual interference between cavitation and a hydraulic system. A stability analysis for the cavitation surge was performed based on the unsteady characteristics of the cavitating pump, tha…
View article: Proposal of Design Method for Viscous Micropumps with a Rotating-Disk Using Theory and Simulation
Proposal of Design Method for Viscous Micropumps with a Rotating-Disk Using Theory and Simulation Open
The aim of the present study is to treat circular- and spiral-shaped viscous micropumps unitarily and provide guidelines for determining the appropriate micropump for performance requirements. Three-dimensional theoretical equations applic…
View article: Study on a microjet generated by two laser-induced cavitation bubbles
Study on a microjet generated by two laser-induced cavitation bubbles Open
Two cavitation bubbles generated by laser irradiation in water generate microjets due to their mutual interference. The characteristics of microjets vary depending on the size and distance of the bubbles, as well as on the time difference …
View article: Fundamental Research on Drag Characteristics of Jet Impinging to Perforated Walls
Fundamental Research on Drag Characteristics of Jet Impinging to Perforated Walls Open
To minimize sa fe distance from hydrogen stations, drag characteristics of jet impinging to perforated walls were investigated. The non-perforated wall and the perforated walls with five different opening rates were tested. The load cells …
View article: A Study on the Process of Low-Frequency Noise Generation in A Multi-Blade Centrifugal Fan
A Study on the Process of Low-Frequency Noise Generation in A Multi-Blade Centrifugal Fan Open
This study numerically investigates the flow characteristics of a multi-blade centrifugal fan in order to identify the process of low-frequency aerodynamic noise generation. Computational analysis has been carried out using the large eddy …
View article: Numerical simulation of the influence of unsteady vortex motion on energy separation in a vortex tube
Numerical simulation of the influence of unsteady vortex motion on energy separation in a vortex tube Open
When a compressed air is supplied tangentially to a vortex tube, the total temperature separation is generated between the cold and hot air outlets by the swirling flow field formed inside the cylinder. By using the vortex tube, the indust…
View article: Jet vectoring using secondary Coanda synthetic jets
Jet vectoring using secondary Coanda synthetic jets Open
In recent years, studies on the fundamental principle of thrust vectoring using jets have been conducted to realize next-generation aircraft applications. Various methods for vector control of jet flow have been proposed, such as methods t…
View article: Study on the Thrust Characteristics of Synthetic Jets
Study on the Thrust Characteristics of Synthetic Jets Open
A synthetic jet has a zero-net mass flow rate at the nozzle outlet but generates a net mass flow rate downstream. Considering the momentum conservation, we supposed that the synthetic jet produces the time-averaged thrust. Furthermore, the…
View article: Study on pressure performance of helical type viscous Micro pump
Study on pressure performance of helical type viscous Micro pump Open
A micropump is a type of small and precise pump, which is mainly used for fuel supply for small fuel cells and liquid transport for biotechnology and medical equipment. However, viscous micropumps are one of the most suitable micropumps to…
View article: Thermodynamic Effect of Tip-Leakage-Vortex Cavitation on Two-dimensional Hydrofoils with Tip Clearance for Hot Water
Thermodynamic Effect of Tip-Leakage-Vortex Cavitation on Two-dimensional Hydrofoils with Tip Clearance for Hot Water Open
Investigation of the thermodynamic effect of tip-leakage-vortex cavitation on a two-dimensional hydrofoil designed with a tip clearance for hot water is reported herein. During unsteady cavitation of water maintained at 90 °C (hereinafter …
View article: Three-Dimensional Theoretical Study on Flow Characteristics of a Spiral-Channel Viscous Micropump
Three-Dimensional Theoretical Study on Flow Characteristics of a Spiral-Channel Viscous Micropump Open
Technological developments have led to micropumps playing an ever-greater role at the heart of micro total analysis systems. Spiral-channel viscous micropumps have been studied theoretically, numerically, and experimentally. However, high-…
View article: Flow Characteristics in a V-shaped Region of a Suction Performance Curve in a Double-suction Centrifugal Pump
Flow Characteristics in a V-shaped Region of a Suction Performance Curve in a Double-suction Centrifugal Pump Open
The present study investigated flow characteristics in the V-shaped region of the suction performance curve for a double-suction centrifugal pump based on the computational fluid dynamics (CFD). The V-shaped region in the time-averaged suc…
View article: Experiments and numerical simulations of a flow instability in a low-specific-speed pump-turbine
Experiments and numerical simulations of a flow instability in a low-specific-speed pump-turbine Open
In order to clarify the mechanism of the fluid oscillation, which occurs for a shut-down sequence of a pump-turbine, the experiment and numerical simulation of the pump-turbine were performed. The pressure fluctuation is measured at inlet,…
View article: Cavitation CFD analyses considering the pressure wave propagation within the piping systems
Cavitation CFD analyses considering the pressure wave propagation within the piping systems Open
Cavitation surge is a typical unsteady phenomenon and can be a cause of severe noise and vibration problems in hydraulic systems. When the oscillation frequency of the piping systems surrounding the hydraulic devices under cavitation surge…
View article: Spectral Decomposition and Reconstruction of Unsteady Flow in a Multi-blade Fan
Spectral Decomposition and Reconstruction of Unsteady Flow in a Multi-blade Fan Open
Multi-blade fan can achieve high pressure and flow rate despite of its small size. However, the fun has still has drawback on the noisegeneration. Although it is required to understand the cause of noise, it is difficult to understand the …
View article: Visualization of breathing mode on releasing bubble
Visualization of breathing mode on releasing bubble Open
Bubble oscillation in the breathing mode at the bubble release was investigated by flow visualization and image processing. The interface amplitude is usually a several micron meter with 1 kHz, so the direct observation is crucially diffic…
View article: Characteristics of heat transfer enhancement in low flow area heat exchanger tubes
Characteristics of heat transfer enhancement in low flow area heat exchanger tubes Open
According to the downsizing of automotive equipment, the present report discussed the heat exchange efficiency in intercoolers used in turbochargers system, etc. Due to the downsizing, low-flow-rate heat exchanger such as installed in a su…
View article: Enhancement of rotating jet by spirally structured vortex tube in centrifugal bladeless mixer flow
Enhancement of rotating jet by spirally structured vortex tube in centrifugal bladeless mixer flow Open
The flow characteristics in a centrifugal bladeless mixer were investigated by using particle image velocimetry (PIV) and large eddy simulation (LES). The numerical result is compared with experimental one in terms of the phase-averaged ve…
View article: A study on separation flow around rotating and non-rotating cylinders with a vortex method
A study on separation flow around rotating and non-rotating cylinders with a vortex method Open
Separation of flows from a surface of an object is deeply related to aerodynamics itsself. In this study, a flow around a cylinder is considered as typical flow around the object. When a cylinder rotates, lift force is generated by the Mag…
View article: Two-Dimensional Theoretical Study on Flow Characteristics of a Spiral-Channel Viscous Micropump
Two-Dimensional Theoretical Study on Flow Characteristics of a Spiral-Channel Viscous Micropump Open
This study investigates the flow characteristics of a spiral-channel viscous micropump using two-dimensional theoretical analysis. The obtained results are compared to the results obtained from experiments, numerical simulations, and the t…