The present study aimed at assessing a novel annular-ducted fan lift system for VTOL aircraft through computational fluid dynamics (CFD) simulations. The power and lift efficiency of the lift fan system in hover mode, the lift and drag in transition mode, the drag and flight speed of the aircraft in cruise mode and the pneumatic coupling of the tip turbine and jet exhaust were studied. The resu...

An experimentalinvestigation has been made of the subsonic lift, drag and longitudinal stability characteristics of models representing some alternative slender airbus configurations. For the same wing planform of aspect ratio 1.4 the lift, drag and pitching moment have been measured for two wings of maximum thickness/chord ratio 4 and 9 per cent respectively, both without and with various body...

SUMMARY An analysis is presented of measurements made at RAE in 1957-1959 on a series of delta wings. Lift and drag have been measured by strain-gauge balance at Mach numbers between 1.4 and 2.8. On some of the wings surface pressure distributions have also been measured. This Report deals mainly with the zero-lift wave drag, but also gives information on skin friction drag and lift-dependent d...

This paper presents results of several large-eddy simulations LES of turbulent flow in an open channel through staggered arrays of rigid, emergent cylinders, which can be regarded as idealized vegetation. In this study, two cylinder Reynolds numbers, RD =1,340 and RD=500, and three vegetation densities are considered. The LES of the lowest density and at RD=1,340 corresponds to a recently compl...

The aim of this paper is to determine the hydrodynamic characteristics of swimmer's scanned hand models for various combinations of both the angle of attack and the sweepback angle and shape and velocity of swimmer's hand, simulating separate underwater arm stroke phases of freestyle (front crawl) swimming. Four realistic 3D models of swimmer's hand corresponding to different combinations of se...

The hydrodynamics of a dispersed air-water system within a spouted column with a concentric draft tube and a conical base is simulated using CFD based on a two–fluid Euler–Euler (E-E) modeling framework and k-ε two-equation turbulence closures. The interaction between the dispersed gas phase and the continuous liquid phase is characterized by bubble–liquid interphase forces (drag, turbulent dis...

Numerical investigation of flow around a square cylinder are presented using the multi-relaxation-time lattice Boltzmann methods at different Reynolds numbers. A detail analysis are given in terms of time-trace analysis of drag and lift coefficients, power spectra analysis of lift coefficient, vorticity contours visualizations, streamlines and phase diagrams. A number of physical quantities mea...

Hypersonic rareŽ ed-gas  ows near two side-by-side plates have been studied numerically with the direct simulationMonte Carlo technique under transitional rareŽ ed-gas- ow conditions (Knudsen numbers from 0.024 to 1.8). Strong in uences of the geometrical factor (ratio of distance between plates to plate length) and the Knudsen number on the  ow structure (the shape of shock waves, the conŽ...

Scour is a phenomenon that occurs as a result of natural erosion by ground water flow and transport of seabed material. In this research, scour around the legs of marine structures is simulated using the FLOW3D.V.9.3™ commercial software. The general scour model consists of two components, namely, the lift and thrust forces. The drag force, that is inserted to the structure, is a combination of...

We have used computational fluid dynamics to study changes in lift generation and vortex dynamics for Reynolds numbers (Re) between 8 and 128. The immersed boundary method was used to model a two-dimensional wing through one stroke cycle. We calculated lift and drag coefficients as a function of time and related changes in lift to the shedding or attachment of the leading and trailing edge vort...