An array of measured device data, a numerical simulator, and process/physics-based compact model are used to gain new important physical insights on nanoscale FinFETs with undoped thin-fin bodies. The insights, which include unavoidable/needed gate underlap, bias-dependent effective channel length, non-ohmic fin-extension voltage drops, reveal the significance positioning on, source/drain doping profile in, thin fin, imply novel modeling that will be needed for optimal design nonclassical...

The lower total temperature and pressure in a dual-mode scramjet engine lead to slower rates of evaporation chemical reactions, while the inflow velocity is higher than that ramjet engine. Consequently, enhancing fuel residence time becomes more critical challenge. cavity crucial device for time. However, quantitative capacity mechanism have not yet been revealed, especially wide-range speed conditions. This work employs delayed detached eddy simulation method investigate mass transport...

A comprehensive theoretical model for the primary breakup of liquid jets in subsonic crossflow was developed. The theoretically analyzed jet deformation process, mass stripping and influence several critical forces consequently provided highly accurate predictions trajectory. Deformation cross section considered as a two-stage process based on physical characteristics, including spring-mass analogy induced deformation. modeled an exponential function time experimental findings droplets....

In the tandem turbine-based combined cycle engine's hyperburner, complex intrusive design is usually employed to achieve ignition and stable combustion under high-speed low-temperature extreme conditions. This paper proposes a concise, non-intrusive coupled swirler-cavity configuration supply fuel with good atomization at cavity-trapped vortex center, thereby ensuring formation of initial flame kernel. Under guidance vortex, kernel grows through dynamic “rotation-diffusion” mechanism....

In shock accelerated flows such as supersonic injection, it is normally recognised that flow structures are well scaled by the characteristic length under continuity hypothesis. By investigating interaction between incident and cylindrical bubbles ranging from dozens of millimetres to micrometres, a breakdown vortex formation observed within Navier-Stokes-suitable scale. The phenomenon characterised specific stretching factor directly reflected decline in normalised circulation. Further...

The lift-off flow of the supersonic streamwise vortex in oblique shock-wave/jet interaction (OS/JI), extracted from a wall-mounted ramp injector scramjet, is studied through large-eddy simulation method. shocked helium jet deforms into pair with co-rotating companion vortex. trajectory center lifted by shock interaction. Based on objective coordinate system frame shock, it found that nature three-dimensional structure OS/JI inherently and precisely controlled kinetics corresponding bubble...

An objective definition for the variable-density mixing rate is still lacking despite its crucial role in understanding ignition/extinction phenomenon. We provide evidence that existence of density gradient accelerated rate, $\ensuremath{\langle}{\ensuremath{\chi}}^{*}\ensuremath{\rangle}$ contributes to an abnormal decrease mean concentration, which distinctly different from previous observations passive scalar mixing. A scaling behavior emerges weak dependence on a broad range P\'eclet...

To investigate the intrinsic mechanism for mixing enhancement by variable-density (VD) behaviour, a canonical VD extracted from supersonic streamwise vortex protocol, shock–bubble interaction (SBI), is numerically studied and compared with counterpart of passive-scalar (PS) mixing. It meaningful to observe that maximum concentration decays much faster in SBI than PS regardless shock Mach number ( $Ma=1.22 - 4$ ). The quasi-Lamb–Oseen-type velocity distribution found analysing azimuthal...

Multidimensional numerical simulations are performed to investigate the evolution and formation of unburned fuels for a shock–fuel jet interaction scenario. A full set Navier–Stokes equations with detailed chemical mechanisms solved, results analyzed through Lagrangian method goal improving combustion efficiency in supersonic flows. The flame morphology two-dimensional (2-D) non-premixed reactive shock–bubble is first simulated studied, which hydrogen found prevent efficient combustion. By...

Abstract Incorrect propagation speed of discontinuities may occur by straightforward application standard dissipative schemes for problems that contain stiff source terms underresolved grids even time steps within the CFL condition. By examining discretized counterpart Euler equations a detonation problem consists single reaction, detailed analysis on spurious wave pattern is presented employing fractional step method, which utilizes Strang splitting. With help physical arguments, threshold...

A method for predicting the residual velocity and deceleration of a projectile during normal low-velocity impact on 2024-O thin aluminium plate is developed based similarity theory. Geometric scaling, dissimilar materials different target thicknesses are considered. By similitude analysis, simulation criteria between modelling prototype experiments obtained. The dimensionless can be predicted by relationship equations with dynamic pressure, density thickness. On basis experimental data,...

Based on the definition of absolute degree grey incidence, which put forward by Professor Liu in 1992, a kind new models for incidence analysis is given this paper. The interrelations and influence can be measured with different visual angle comparability closeness respectively. And simplified method to calculate similitude close are proved. properties studied. Compared original definition, many advantages prone practical applications.

The venturi mixer is one of the key structures fully premixed surface natural gas burner. It has function uniformly mixing and air in a specific fluid space. In order to improve burn-up rate combustion, make combustion temperature lowered reduce emission NOx pollutants, two-channel was designed, according performance pressure loss uniform. structure analyzed by numerical simulation with evaluation uniform parameters from downstream following isometric characteristic cross-sectional. results...