The aerodynamic drag coefficient of a train CD, is given by: CD =D/1/2pA V 2 (1) where D is the drag force in zero cross-wind, V is the train velocity, A is a reference frontal area and p is the density of air.

The velocity may be that of the object through the air (or any other gas) or the air velocity past a stationary object. The coefficient of rolling friction is much lower than the coefficient of static friction, which would apply if the wheel were not allowed to rotate and would have to slide. The coefficient of rolling friction for a wheel-rail interface is approximately 0.001, while the coefficient of static friction for a steel-on-steel interface is approximately 0.5. A moving model test method based on stagnation pressure measurements is proposed to measure the train aerodynamic drag coefficient.

The drag coefficient is a function of several parameters like shape of the body, Reynolds Number for the flow, Froude number, Mach Number and Roughness of the Surface.

The reduction of drag in road vehicles has led to increases in the top … The drag coefficient (non-dimensional drag) is equal to the drag force divided by the product of velocity pressure and frontal area. As a reference, arrows with velocities over 200 ft/s experience more drag deceleration than gravitational acceleration. As an approximation one may We have used Creo as our design software and Ansys Fluent for the fluid (air) flow analysis with varying parameters. AeroEfficient shaping of trains is carried out in design software and tested out using wind tunnel analysis to determine drag coefficients and drag forces. Aerodynamic modelling of trains directly influences power consumption and fuel efficiency. Which means that the drag coefficient of trailer increased by 15.8% [10]. Cd is the drag coefficient (dimensionless) A is the cross sectional area of the projectile ... Not surprisingly, a rrows travel at least 4 to 5 times further than bird shot. Objects drag coefficients are mostly results of experiments.

They are usually used to calculate vehicle speed calculations based upon tyre mark geometry. Drag factor and coefficient are expression commonly used in crash investigation and reconstruction. Of course, these forces are not oriented in the same direction. Because the front tip of a high-speed train has a high pressure area and because a stagnation point occurs in the center of this region, the pressure of the stagnation point is equal to the dynamic pressure of the sensor tube based on the obtained train velocity. The characteristic frontal area - A - depends on the body. The drag coefficient value only for semi-truck is 0.608, and for truck with trailer is 0.704. Reducing Aerodynamic Drag and Fuel Consumption Year 2002 statistics for combination trucks (tractor-trailers) on nation’s highways * 2.2 million trucks registered 138.6 billion miles on nation’s highways, 3-4% increase/yr 26.5 billion gallons diesel fuel consumed, 4-5% increase/yr 5.2 mpg, or 19.1 gallons/100 miles ~ 2.47 million barrels/day ** Reducing drag. REES Module #3 - Train Energy, Power and Traffic Control 17 Train resistance and tractive effort are both measurements of force (typically in pounds in North America) so we can simply overlay the curves Coefficient of friction vs Drag factor. Coefficients are given for a number of geometrical shapes and also for cars, airships and struts.