A simple quantitative test is described for measuring the duration of post-traumatic amnesia. It was used in a study 336 patients with closed head injury; and results matched closely independent estimates experienced neurosurgeons. systematic procedure this kind clinically useful its sensitivity to fluctuations or deterioration patient's mental state. could also be advantage multi-centre research by providing standard criterion assessment

The 3-point static belts that are installed in Renault and Peugeot vehicles equipped with a force limiter near the upper anchorage. This system is made up of several bands textiles tear successively for increasing levels exerted by occupant. One can thus associate, each person accident, degree thoracic AIS value support force, expressed daN. relationship established 92 belted occupants who were involved frontal impacts. In addition it indicated which distributions impact violence parameters...

The spatiotemporal development of impulsively excited two-dimensional linear disturbances in acceleration-skewed and velocity-skewed Stokes layers is investigated using numerical simulations the linearized Navier–Stokes equations. This study focuses on long-term behavior linearly unstable within these skewed flows. onset instability symmetric layer known to coincide with absolute instability, forming family tree structures, characterized by multiple wavepackets spread across plane, coupled...

The linear stability of confined, periodic, parallel fluid flows is examined. flow fields considered consist a steady pressure gradient-driven velocity field combined with purely oscillatory component generated by either an gradient or harmonically oscillating bounding surfaces. Plane channel and circular pipe geometries are studied all possible combinations the components investigated. Neutral curves critical conditions for instability computed selection steady–unsteady ratios, half-widths...

A linear stability investigation is undertaken on the two-dimensional flow that develops in a channel whose walls are coated with superhydrophobic material. The surfaces modeled as classical slip surfaces, exploiting Navier condition imposed walls. Both symmetric and asymmetric considered, whereby linearized of determined via an Orr–Sommerfeld normal-mode approach. In both instances, application establishes significant stabilizing effect increases critical Reynolds number associated onset...

Abstract Quantitative results for the linear stability of planar Stokes layers subject to small, high-frequency perturbations are obtained both a narrow channel and flow approximating classical semi-infinite layer. Previous theoretical experimental predictions critical Reynolds number flat layer have differed widely with former exceeding latter by factor two or three. Here it is demonstrated that only 1 % perturbation, at an appropriate frequency, nominal sinusoidal wall motion enough result...

Abstract Numerical simulation results are presented for the linear and nonlinear evolution of disturbances in a flat Stokes layer. The response to spatially localised impulsive forcing is investigated it found that spatial–temporal development flow displays an intriguing family-tree-like structure, which involves birth successive generations distinct wavepacket components. It shown some features this unexpected structure can be predicted using stability analysis based on Floquet theory.

Abstract A numerical study is conducted to investigate the influence of a uniform axial magnetic field on global linear stability rotating-disc boundary layer. Simulation results obtained using radially homogenized base flow were found be in excellent agreement with an earlier analysis, which indicated that can locally suppress both convective and absolute instabilities. However, for genuine, inhomogeneous, indicate form instability develops sufficiently large fields. The qualitative nature...

The effect of a small Gaussian shaped deformation on the development and growth Tollmien–Schlichting disturbances an unswept airfoil is investigated. A broad range gap depths widths modeled that can be sufficient to generate localized pockets reverse flow. Boundary-layer profiles are computed using Navier–Stokes solver, permitting thorough investigation all configurations considered. linear stability waves then examined parabolized equations linearized formulations, with former method giving...

An adjoint approach is developed to undertake a receptivity study of the rotating disk boundary layer. The linearized Navier–Stokes equations are first derived in cylindrical coordinates. A formula then formulated that specifies response stationary and traveling linear perturbations an external force, including sources momenta mass unsteady wall motion. Using parallel flow approximation, which radial dependence undisturbed ignored, characteristics computed for broad range temporal...

The frequency and severity of lesions sustained by the occupants cars impacted laterally depend upon main following factors: impact localization, intrusion into passengers' compartment, car speed variation, direction occupant trajectory, objects contacted various body areas. paper describes results studies 296 lateral impacts. It draws conclusions as to coming improvement protection, taking account current state art in biomechanics automobile design.

Numerical simulations were conducted to investigate the effects of surface suction and injection on global behaviour linear disturbances in rotating-disk boundary layer. This extends earlier work, which considered case with no mass transfer. For genuine base flow, where radially inhomogeneity is retained, at disk led that remained qualitatively similar was found when there The initial development within absolutely unstable region involved temporal growth upstream propagation, as should be...

An investigation is made of the three-dimensional linear stability Stokes layer generated within a fluid contained inside long oscillating cylinder. Both longitudinal and torsional vibrations are examined system disturbance equations derived using Floquet theory solved pseudospectral methods. Critical parameters for instability obtained an extensive range pipe radii azimuthal wavenumbers. For sufficiently small diameters, perturbations sometimes found to be more unstable than their...

A scheme for generating boundary layers is described and applied to an infinite swept wing model with wavy surface deformations. Steady laminar mean flow extracted directly from solutions of the Navier–Stokes system equations, which validated against computations a compressible boundary-layer method. Furthermore, routines capture separated profiles, overcoming constraints conventional methods. The stability crossflow disturbances investigated using both parabolized equation linearized...

A numerical investigation is undertaken on the effect of small-scale surface roughness local absolute and global stability flow due to a rotating disk. Surface modeled via imposition partial-slip wall boundary condition, with radial concentric anisotropic roughnesses isotropic considered. The parameters neutral characteristics for instability presented, while azimuthal mode numbers required linear occur are determined genuine inhomogeneous base flow. Predictions threshold values needed...

Linear disturbance development in the von Kármán boundary layer on an infinite rotating-disc is investigated for extensive range of azimuthal mode numbers $n$ . The study expands upon earlier investigations that were limited to those values located near onset absolute instability (Lingwood, J. Fluid Mech. , vol. 299, 1995, pp. 17–33), where disturbances genuine inhomogeneous flow shown be globally stable (Davies & Carpenter, 486, 2003, 287–329). Numerical simulations corresponding...

Wavy surface variations establish separation bubbles on an unswept wing. The development of Tollmien-Schlichting disturbances are investigated, and PSE analysis is shown to agree with LNS solutions for some configurations.

A numerical study on the effect of surface slip flow in a constricted channel is presented, with aim exploring use to control separation. Our focus two-dimensional over bump, fixed aspect ratio, upon which Robin-type boundary condition imposed. When walls are fully no-slip, such known develop region separation behind at sufficiently large Reynolds numbers. The bubble dynamics occurring bump investigated, for numbers $2000$ and $4000$ . It shown that (i) attenuates intensity as it diminishes...

The receptivity of crossflow disturbances on an infinite swept wing is investigated using solutions the adjoint linearised Navier-Stokes equations. based method for predicting magnitude stationary generated by randomly distributed surface roughness described, with analysis extended to include both curvature and compressible flow effects. Receptivity predicted a broad spectrum spanwise wavenumbers, variable freestream Reynolds numbers, subsonic Mach numbers. Curvature found play significant...

Surface slip, characterized by a slip length, $\ensuremath{\lambda}$, suppresses flow separation induced Gaussian-shaped deformations on flat plate. Bumps generate more intense regions of reversed than gaps, requiring larger $\ensuremath{\lambda}$ to inhibit separation. The study extends double-bump configurations, where the distance between bumps establishes either stabilizing effect or nonlinear oscillatory flow. However, increasing ultimately this phenomenon and eliminates all pockets separated