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Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion; turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities. [10] The Reynolds number is defined as: [6]
A crossflow head gives better performance than a Reverse-flow cylinder head (though not as good as a uniflow), but the popular explanation put forward for this — that the gases do not have to change direction and hence are moved into and out of the cylinder more efficiently — is a simplification since there is no continuous flow because of valve opening and closing.
Drag coefficients in fluids with Reynolds number approximately 10 4 [1] [2] Shapes are depicted with the same projected frontal area. In fluid dynamics, the drag coefficient (commonly denoted as: , or ) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water.
The main advantage of the reverse-flow cylinder head is that both the entering inlet charge and the exiting exhaust gas cause a tendency to swirl in the same direction in the combustion chamber. [1] In a crossflow head the inlet and exhaust gases promote swirl in opposite directions so that during overlap the swirl changes directions.
This reduces repair costs as a single failed head on a single cylinder can be changed instead of a larger, much more expensive unit fitting all the cylinders. Such a design also allows engine manufacturers to easily produce a 'family' of engines of different layouts and/or cylinder numbers without requiring new cylinder head designs.
Originally developed in 1959 for the Ford Anglia, it is an in-line four-cylinder overhead valve (OHV) pushrod engine with a cast-iron cylinder head and block. The Kent family can be divided into three basic sub-families; the original pre-Crossflow Kent, the Crossflow (the most prolific of all versions of the Kent), and the transverse mounted ...
Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve their air flow. Cylinder heads, as manufactured, are usually suboptimal for racing applications due to being designed for maximum durability. Ports can be modified for maximum power, minimum fuel consumption, or a ...