The formation and evolution of 3D synthetic jets is examined using direct numerical simulations. The primary focus of the current study is on examining the formation of 3D synthetic jets and the effect of changes in the jet aspect-ratio on the flow produced by the jet. Jets in quiescent and cross-flow cases are investigated. The study compares the vortex dynamics, velocity profiles and the othe...

SUMMARY An experimental study has been made of an incompressible turbulent plane jet exhausting downstream into an external flow having a favourable longitudinal pressure gradient approximating that of two-dimensional sink flow. Four flows were studied, for which the ratios of mainstream and jet velocities at the exit plane of the jet were in the range from 0.1 to 0.5. For each case velocity pr...

Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier-Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-c...

We derive an analytical form for jet-correlation flow-background in a cluster approach. We argue that the elliptic flow parameter to be used in jetcorrelation background is that from two-particle method excluding non-flow correlation irrelevant to reaction plane, but including cross-terms between cluster correlation and cluster flow. We verify our result with Monte Carlo simulations. We discuss...

In this paper, the acoustic excitation effects on the flow characteristics of a laminar jet inside an air-filled cylindrical tube have been presented and discussed. It is observed that the acoustic excitation has a strong effect on the jet velocity and its flow structure. Under excitation, the velocity is observed to increase more than seven times. Comparisons and investigations of the velocity...

The oscillatory flow through tapered cylindrical tube sections (jet pumps) is characterized by a numerical parameter study. The shape of a jet pump results in asymmetric hydrodynamic end effects which cause a time-averaged pressure drop to occur under oscillatory flow conditions. Hence, jet pumps are used as streaming suppressors in closed-loop thermoacoustic devices. A two-dimensional axisymme...

The purpose of the present study is to clarify the heat transfer characteristics with multiple jet impingement aiming at the highly efficient cooling performance. In the study, we investigated the effect of injection parameters on circular jet array impingement heat transfer. As we focus on interference among the adjacent impinging jets, tests are mainly conducted at the minimum crossflow condi...

Turbulence in fluids is commonly observed to coexist with relatively large spatial and temporal scale coherent jets. These jets may be steady, vacillate with a definite period, or be irregular. A comprehensive theory for this phenomenon is presented based on the mutual interaction between the coherent jet and the turbulent eddies. When a sufficient number of statistically independent realizatio...

Jet impingement heat transfer is an effective and practical approach that is employed in many industrial processes where heating, cooling, or drying is required. Details of the heat or mass transfer rate have been investigated both experimentally and numerically and can be found in the published literature. In most of the numerical studies, control-volume approach has been employed to solve the...

Recently, particular attention has been paid to the stepped spillways due to the increasing effect of energy dissipation and the reduction of cavitations risks with the development of Roller Compacted Concrete (RCC) technique. Flow regimes on the spillways divide into three groups, namely skimming, jet and transition flow. Compared to the numerical methods, the majority of performed studies in ...