The influence of leading-edge separation vortices on the Weis-Fogh (1973) lift- generation mechanism for insect hovering is investigated. analysis employs a vortex-shedding model (Edwards 1954; Cheng 1954) and represents an extension Lighthill's (1973, 1975) inviscid without separated vortices. Results study compare reasonably well with observations laboratory at high Reynolds number (Maxworthy 1979), confirming that vortex significantly enhances initial circulation each wings. Unlike un-...

The theory of an oscillating, high-aspect-ratio, lifting surface with a curved centreline (Cheng & Murillo 1984) is applied to performance analysis lunate-tail swimming propulsion. Thrust, power and propulsive efficiency are calculated for model lunate tails various combinations mode shapes morphological features ascertain the viability proportional-feathering concept, determine influence sweep curvature. One principal conclusions concerns interchangeability heaving amplitude peduncle...

The asymptotic theory of a high-aspect-ratio wing in an incompressible flow is generalized to oscillating lifting surface with curved centreline the domain where reduced frequency based on half-span order unity. formulation allows applications lightly loaded models lunate-tail swimming and ornithopter flight, provided that heaving displacement does not far exceed mean chord. analysis include quasi-steady limit, which crescent-moon problem considered earlier by Thurber (1965) solved several...

A detailed treatment of inviscid hypersonic flow past a circular cone is given, for small and moderate yaw angles, within the fremework shock-layer theory. The basic problem non-uniform validity associated with singularity entropy field examined valid first-order solution obtained which provides an explicit description thin vortical layer at inner edge shock layer. Analytic formulas pressure circumferential velocity are given consistent to second-order approximation including non-linear...

With the increasing severity of climate change, Carbon Capture, Utilization, and Storage (CCUS) technology has become essential for reducing atmospheric CO2. Marine carbon sequestration, which stores CO2 in seabed geological structures, offers advantages such as large storage capacity high stability. Cryogenic hoses are critical ship-to-ship transfer liquid from transportation vessels to offshore sequestration platforms, but their design methods mechanical analysis remain inadequately...

Introduction O as well new hypersonic flow programs continue to challenge the aerospace engineer. These are often of consuming difficulty, involving synthesis chemical kinetics, quantum mechanics, and radiation physics with fluid dynamics. To further complicate matters, flowfield is rarefied; thus Knudsen number requires independent consideration along Mach Reynolds numbers. Although these parameters related, different regions flow, such interior a bow shock, depend differently on them...

Issues and advances in current hypersonic flow research perceived to be of interest theoretical fluid/gas dynamics are reviewed. Particular attention is given the aircraft as waverider, computational methods development study viscous interaction, boundary-layer instability transition studies. In present framework faces problems two kinds which represent major areas research: turbulence high Re range free-molecule limit.

The inviscid transonic flow past a thin wing having swept leading edges, with smooth lift and thickness distributions, is shown to possess an outer nonlinear structure determined principally by line source doublet. Three domains (the thickness-dominated, the intermediate, lift-dominated), representing different degrees of control flow, are identified; equivalence rule valid in all three established. Except one domain, departure from Whitcomb-Oswatitsch area significant; equivalent body...

Existing analytical treatments of the hypersonic strong interaction problem adopt two-region structure classical boundary-layer theory; however, uneven heating and external vorticity created by highly curved, leading-edge shock wave leads to question uniform validity approximation near edge. Recently Bush (1966), using a non-linear viscosity-temperature law (μ ∞ T ω , < 1) instead linear one ) used previous investigators, demonstrated need analyze separately transitional layer...

The study extends Prandtl's lifting-line theory to planar wings involving swept and curved centerlines. Attention is focused on distinct features of such a theory, with special emphasis an oblique wing in steady incompressible potential flow. analysis presented compared exact solutions derived from inverse method results panel method.

Inviscid–viscous interaction in a high supersonic flow is studied on the triple-deck scales to delineate wall-temperature influence structure region near laminar separation. A critical range O ( T w *) identified, which pressure–displacement relation governing lower deck departs from that of classical (Stewartson, Messiter, Neiland) formulation, and below undergoes still greater changes along with drastic scale triple deck. The reduced lower-deck problem falls into three domains: (i)...

Shock-fitting is applied to relaxation solutions of transonic small-disturbance equations. Finite-difference algorithms expressing conservation laws across the discontinuity are introduced in a manner consistent with type-sensitive difference schemes Murman and Cole. Results presented for flows involving embedded as well bow shocks. Comparison shock-capturing based on shock-point operator (SPO) made same grid comparable computation time. Substantial improvement accuracy by shockfitting...

The problem of how to speed up the convergence currently available iterative methods for transonic flow computations with minimal alterations in computer programing and storage is considered. A cyclic procedure applying nonlinear sequence transformations akin those Aitken Shanks developed. Based on power method, errors these are studied. Examples testing model Dirichlet problems thin airfoil show that savings time a factor two five, or more, generally possible, depending accuracy...

The inviscid flow above an obstacle in slow transverse motion inside a rotating vessel is analysed to study the influence of container depth on basic steady structure. An asymptotic theory presented for arbitrarily small Rossby number Ro = U 0 /2Ω l under fixed H hRo / (where Ω angular velocity container, relative vessel, h and body length measured transversely rotation axis). equations when linearized thin or shallow topography take form inertial-wave equation; their solutions non-vanishing...

Unsteady effects in a separated recirculating eddy beneath subsonic or supersonic mainstream are considered, with emphasis on nonlinear properties. The is slender and predominantly inviscid, its length being comparable with, less than, the chord of an airfoil, for instance. It found, from study family integro-differential equations, that planar can break up nonlinearly within finite time, causing eruption into main stream setting subsequent Euler stage unsteady motion. Comparisons recent...

A transonic-flow theory of thin, oblique wing high aspect ratio is presented, which permits a delineation the influence sweep, centre-line curvature, and other three-dimensional (3D) effects on nonlinear mixed flow in framework small-disturbance theory. In (parameter) domain interest, field far from section pertains to subsonic, or linear sonic, outer flow, representable by Prandtl–Glauert solution involving swept, as well curved, lifting line leading approximation.Among 3D one arising...

Sonic-boom noise penetrating under a deep ocean is affected by its time-dependent interaction with the surface waves, which can significantly influence perceived sound pressure level and tonal content of disturbances at depth far greater than expected from flat-ocean (Sawyers) model. The present theory assumes small slope high water-to-air density ratio; in analysis modelled sinusoidal surface-wave train. shows that distinct acoustic wave mode form packet wavelets emerges field below...