A rational basis for correlating turbulent burning velocities is shown to involve the product of Karlovitz stretch factor and Lewis number. generalized expression derived show how flame related velocity field. new dimensionless correlation experimental values presented. Dimensionless groups also are used in correlations laminar extinction rates. distribution function rates flames, based on an earlier one Yeung et al ., proposed data well predicted by a theory flamelet with this distribution....

The interactions between longitudinal vortices and accompanying waves considered here are strongly nonlinear, in the sense that mean-flow profile throughout boundary layer is completely altered from its original undisturbed state. Nonlinear vortex flow Tollmien-Schlichting addressed first, some analytical computational properties described. These include possibility spatial-development case of a finite-distance break-up, inducing singularity displacement thickness. Second,...

Journal Article On the High Reynolds Number Theory of Laminar Flows Get access F. T. SMITH Mathematics Department, Imperial CollegeLondon, S.W.7 Search for other works by this author on: Oxford Academic Google Scholar IMA Applied Mathematics, Volume 28, Issue 3, May 1982, Pages 207–281, https://doi.org/10.1093/imamat/28.3.207 Published: 01 1982 history Received: 06 November 1980 Revision received: 11 1981

The motion of fluid through an indented non-symmetric channel or symmetric pipe is considered when the flow ahead indentation fully-developed and typical Reynolds number, K, large. theoretical description, for steady flows slowly-varying indentations, founded on a three-region structure, according to which main core suffers small inviscid displacement its streamlines while viscous close walls nonlinear forced along by induced pressure-gradient. can be shown average wall displacements, but...

The asymptotic theory for the laminar, incompressible, separating and reattaching flow past bluff body is based on an extension of Kirchhoff's (1869) free-streamline solution. field (only upper half which discussed since we consider a symmetric flow) consists two basic parts. first scale l *, described to leading order by Kirchhoff solution with smooth inviscid separation, but $O(Re^{-\frac{1}{16}})$ modification explain fully viscous separation (here Re ([Gt ] 1) Reynolds number). influence...

Sychev’s (1972) proposal, that in general the laminar separation and breakaway of an incompressible fluid streaming past a smooth surface (e. g. on bluff body) takes place through triple-deck structure around point, is examined numerically this paper. The proposed pattern for large Reynolds number ( Re ) flows based modification classical Kirchhoff (1869) free streamline theory, which slight adverse pressure gradient provoked inviscid motion immediately ahead breakaway. This just enough to...

Abstract The breakdown and separation or reattachment of boundary layers adjoining a mainstream are studied in the three related situations (i)-(iii) title. For (i) classical steady layer generally admits logarithmic singularity displacement when occurs on downstream-moving surface whereas corresponding for an upstream-moving can be minus-one-sixth form. Conversely, delayed to onset zero flow, which case is again logarithmic. In certain flows these singularities prove removable locally,...

A shallow three-dimensional hump disturbs the two-dimensional incompressible boundary layer developed on an otherwise flat surface. The steady laminar flow is studied by means of a extension triple-deck theory, so that there prospect separation in nonlinear motion. As first step, however, linearized analysis valid for certain obstacles gives some insight into properties. most striking features then are reversal secondary vortex motions and emergence ‘corridor’ wake hump. corridor stays...

The characteristics of some flows that occur when fluid is driven through a curved tube are disclosed for an imposed pressure gradient pulsatile nature, varying sinusoidally with time about non-zero mean. fully developed motion depends on three parameters, traditional Dean number D , frequencyrelated parameter β and secondary Reynolds R s it being assumed the pipe's radius curvature much greater than its cross-sectional dimensions. theoretical description flow field extended from steady...

A complete description is sought for the two-dimensional laminar flow response of an incompressible boundary layer encountering a hump on otherwise smooth boundary. Given that typical Reynolds number Re (based development length L* layer) large, characteristics depend only two parameters, non-dimensional and height scales l, h obstacle. For short humps less than familiar O(Re−⅜) triple-deck size critical scale, which produces nonlinear interaction hence prospect separation, order . Height...

An investigation is described for the nonlinear stability, at large Reynolds numbers R , of Hagen-Poiseuille flow through a pipe circular cross section when subjected to three-dimensional disturbances typical relative size δ enough yield only vanishingly small phase shift across critical layer. A crucial = O ( -⅓ ) since then this in tune with produced by viscous wall layers. The layer, which fully and three-dimensional, layers, where disturbance greater than basic reversal occurs, are...

The axisymmetric flow of an incompressible fluid through a pipe (of radius a) suffering severe constriction is studied for large Reynolds numbers R, the features symmetric channel flows being virtually same. Here 'severe' refers to whose typical dimensions are finite, and oncoming velocity profile taken be realistic type, i.e. with no slip at wall. study adopts (Kirchhoff) free-streamline theory, which, mostly inviscid description, affords rational basis consistent viscous separation. major...

The effect of increasing disturbance size on the stability a laminar streaming flow is considered theoretically at high Reynolds numbers Re. theory has rational basis that allows detailed understanding delicate physical balances controlling stability, and presented with an accelerating boundary layer taken as basic flow. predicts scales properties required to produce Rayleigh situation (where disturbances have wave speed wavelength comparable typical thickness respectively flow) in neutral...

The manner in which fluid driven through a channel of width responds anticipation severe asymmetric distortion (e.g. to the wall or interior conditions downstream) is discussed when oncoming flow fully developed, characteristic Reynolds number K large and whole motion remains laminar. Far ahead disturbance, at distances particular finite distortion. Comparisons this other predictions with computed solutions full Navier–Stokes equations show reasonable agreement.

In this paper we consider the problems of radiation and scattering surface gravity waves by a vertical circular cylinder placed on centreline channel width 2 d depth H , either extending from bottom through free or truncated so as to fill only part depth. These are solved, for arbitrary incident wavenumber k constructing appropriate multipoles cylinders symmetrically in channels then using body boundary condition derive set infinite systems linear algebraic equations. For general considered...

The initial stages of high-velocity droplet impact on a shallow water layer are described, with special emphasis given to the spray jet mechanics. Four delineated, appropriate scalings, and successively more important influence base is analysed. In particular, there finite time before which part in remains under after all ejected splash jet.

Indented tube flows are discussed when the characteristic Reynolds number K is large, oncoming flow fully developed and indentations slowly varying. The range of theory in an allied paper (1) extended to steady or unsteady asymmetric channel with α = O(K–1), symmetric where a typical slope constriction. In first regime here upstream interaction takes place over large length scale, forced by transverse pressure gradient acting core, although oscillations sufficiently high frequency wall shape...

Journal Article Boundary Layer Flow near a Discontinuity in Wall Conditions Get access F. T. Smith Department of MathematicsImperial College, London SW7 2AZ Search for other works by this author on: Oxford Academic Google Scholar IMA Applied Mathematics, Volume 13, Issue 2, April 1974, Pages 127–145, https://doi.org/10.1093/imamat/13.2.127 Published: 01 1974 history Received: 10 December 1972 Revision received: 16 July 1973

Analytical and numerical properties are described for the free interaction separation arising when induced pressure local displacement equal, in reduced terms, large Reynolds number flow. The interaction, known to apply hypersonic flow, is shown have possible relevance also origins of supercritical (Froude > 1) hydraulic jumps liquid layers flowing along horizontal walls. main theoretical task obtain ultimate behaviour far beyond separation. An unusual structure found emerge there, involving...

The effect of surface roughness on droplet impact is considered. If a sufficiently rough, then models need to be altered include the possibility many touchdowns between fluid and solid. subsequent simultaneous motion several contact points therefore described. In particular, results are presented for point during sheet water periodic rough surface. A model multiple also analysed cases deep roughnesses. analysis complemented by direct numerical simulation using volume method. reduce rate at...

For practically uniform entry conditions, the features of steady laminar flow produced by a particular small distortion walls channel or pipe are shown to alter first from those corresponding external situation when is in an ‘adjustment zone’, sited large distance O(R⅗l) inlet; R ([Gt ] 1) and l signify respectively typical Reynolds number length scale incompressible fluid motion. The planar there develops extended triple-deck structure, with unknown inviscid core motion bounded two-tiered...