The evolution of unidirectional wave trains containing a that gradually becomes steep is evaluated experimentally and numerically using the Boundary Element Method (BEM). boundary conditions for nonlinear numerical simulations corresponded to actual movements wavemaker paddle as recorded in physical experiments, allowing direct comparison between measured experiments’ characteristics train predictions. high level qualitative quantitative agreement measurements validated kinematic criterion...

A new pumpless liquid cooling system for a single-stage two-cylinder reciprocating compressor has been developed from the analysis of work processes and systems compressors, where one piston compresses moves gas coolant in system. The intensification movement increases machine, which can reduce temperature cylinder–piston group increase indicator efficiency feed rate. mathematical model working its on basic fundamental laws conservation energy, mass motion. prototype was tested to obtain...

The adjoint thermodynamic and heat exchange processes in the new class piston compressor with regenerative are considered paper. implicit tridiagonal matrix algorithm is implemented to study unsteady thermal conductivity cylinder–piston group. After formulation of proper initial boundary conditions, optimal relationship between temporal spatial discretization steps determined. Two different time used numerical solution two-way coupled fast slow models. those determined as well. conducted...

Abstract Evaluation of localized and distributed in time spectral energy wave–current coexisting environment is investigated this study. In order to understand the inherent characteristics flow under consideration, Hilbert-Huang transform (HHT) introduced determine instantaneous frequency corresponding maximum carrying by velocity field. This associated with timescale most energetic fluctuations. The intrinsic mean mode function (IMF) reduced increase IMF number. It was shown that...

Предложена математическая модель процесса

A method for the generation of steep nonlinear broad-banded wave trains having an arbitrary prescribed shape is developed. It shown that second-order contributions to velocity field are negligible in deep water, while bound components surface elevation significant. This fact allows improvement iterative wavemaker driving signal adjustment increases accuracy excitation train with free waves’ spectrum. The decomposition complex amplitude spectrum into and based on approach adopted derivation...

Some results of investigation energy separation mechanism included in numerical model equations air spiral flow appearing Ranque-Hilsch vortex tube are presented the article. Standard k-ε turbulence had been used simulations. It was found that make possible to predict effect by using special semi empirical term conservation equation which accounts for heat conductivity effects.

Wind effects on wave overtopping over a fully impermeable vertical sea wall were studied numerically using the open-source computational fluid dynamics library OpenFoam. A pressure gradient correction term was incorporated in momentum equations. In recent studies, it found that, absence of wind, an increase steepness results reduction overtopping. This is related to instability standing formed at front structure. Such noticed range 0.285–0.443 from previous physical experiments for regular...

Excitation of steep unidirectional broad-banded wave trains is studied numerically and experimentally. Iterative method developed to adjust the driving signal a paddle-type wavemaker generate train with prescribed free waves’ spectrum. Analytical post-processing procedure based on Zakharov equation applied separate complex amplitude spectrum surface elevation into bound components, as required for proposed adjustment signal. Numerical tank in simulations was application Boundary Element...

Abstract Analytic method for nonlinear wave generation by a wavemaker that is somewhat different from the theory of Schäffer proposed. The based on Nonlinear Schrödinger (NLS) equation and boundary condition at free 2nd order limitation inherent to existing theories. Advantages offered NLS model allowed simplification expressions determination driving signal thus made them easily applicable in practice. correction calculated complex surface elevation envelope obtained as solution prescribed...

Abstract Enhancement of the cold flow deceleration unit is considered in paper to improve energetic efficiency vortex tube. It was shown that gradual expansion cross-section diffuser inefficient for reducing gas velocity presence its significant rotation. Installation a blade grid at entrance suggested interruption swirling. A notable reduction energy losses has been demonstrated improving

We present an investigation of the fundamental physical processes involved in deep-water gravity wave breaking. Our motivation is to identify underlying reason causing deficiency eddy viscosity breaking model (EVBM) predicting surface elevation for strongly nonlinear waves. Owing limitation experimental methods provision high-resolution flow information, we propose a numerical methodology by developing EVBM enclosed standalone fully quasi-potential (FNP) and coupled FNP plus Navier–Stokes...