Aerodynamic drag

About: Aerodynamic drag is a research topic. Over the lifetime, 5243 publications have been published within this topic receiving 78004 citations.

Drag reduction fundamentals

Abstract: Drag reduction by dilute solutions of linear, random-coiling macromolecules in turbulent pipe flow is reviewed. The experimental evidence is emphasized in three sections concerned with the graphical display of established features of the phenomenon, data correlation and analysis, and the physical mechanism of drag reduction. This work has application to increased pipelines capacity, the study of wall turbulence and molecular rheology.

Some salient features of the time - averaged ground vehicle wake

Abstract: For a basic ground vehicle type of bluff body, the time averaged wake structure is analysed. At a model length based reynolds number of 4.29 million, detailed pressure measurements, wake survey and force measurements were done in a wind tunnel. Some flow visualisation results were also obtained. Geometric parameter varied was base slant angle. A drag breakdown revealed that almost 85% of body drag is pressure drag. Most of this drag is generated at the rear end. Wake flow exhibits a triple deck system of horseshoe vortices. Strength, existence and merging of these vortices depend upon the base slant angle. Characteristic features of the wake flow for the low drag and high drag configurations is described. Relevance of these phenomena to real ground vehicle flow is addressed.

Aerodynamics of Road Vehicles

Abstract: Contents: Introduction to automobile aerodynamics. Some fundamentals of fluid mechanics. Performance of cars and light vans. Aerodynamic drag of passenger cars. Driving stability in side winds. Operation, safety and comfort. High performance vehicles. Commercial vehicles. Engine cooling systems. Heating, ventilation and air conditioning of motor vehicles. Wind tunnels for automobile aerodynamics. Measurement and test techniques. Numerical methods for computation of flow around road vehicles.

Fluid Dynamic Drag: Practical Information on Aerodynamic Drag and Hydrodynamic Resistance

Abstract: Fluid-dynamic drag: practical information on aerodynamic drag and hydrodynamic resistance , Fluid-dynamic drag: practical information on aerodynamic drag and hydrodynamic resistance , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Drag and drag partition on rough surfaces

Abstract: An analytic treatment of drag and drag partition on rough surfaces is given. The aims are to provide simple predictive expressions for practical applications, and to rationalize existing laboratory and atmospheric data into a single framework. Using dimensional analysis and two physical hypotheses, theoretical predictions are developed for total stress (described by the square root of the canopy drag coefficient), stress partition (described by the ratio Τ S/Τ of the stress Τ s on the underlying ground surface to total stress Τ), zero-plane displacement and roughness length. The stress partition prediction is the simple equation τS/τ= 1/(1+βλ), where λ= CRCS the ratio of element and surface drag coefficients. This prediction agrees very well with data and is free of adjustable constants. Other predictions also agree well with a range of laboratory and atmospheric data.