Search results
Results from the WOW.Com Content Network
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.
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.
Strouhal number (Sr) as a function of the Reynolds number (R) for the flow past a long circular cylinder. For large Strouhal numbers (order of 1), viscosity dominates fluid flow, resulting in a collective oscillating movement of the fluid "plug". For low Strouhal numbers (order of 10 −4 and below), the high-speed, quasi-steady-state portion ...
In a piston engine, the cylinder head sits above the cylinders, [1] forming the roof of the combustion chamber. In sidevalve engines the head is a simple plate of metal containing the spark plugs and possibly heat dissipation fins .
This is a torispherical head also named Semi ellipsoidal head (According to DIN 28013). The radius of the dish is 80% of the diameter of the cylinder ( r 1 = 0.8 × D o {\displaystyle r_{1}=0.8\times Do} ).
For flow in a pipe of diameter D, experimental observations show that for "fully developed" flow, [n 2] laminar flow occurs when Re D < 2300 and turbulent flow occurs when Re D > 2900. [ 13 ] [ 14 ] At the lower end of this range, a continuous turbulent-flow will form, but only at a very long distance from the inlet of the pipe.
In engineering, the Moody chart or Moody diagram (also Stanton diagram) is a graph in non-dimensional form that relates the Darcy–Weisbach friction factor f D, Reynolds number Re, and surface roughness for fully developed flow in a circular pipe. It can be used to predict pressure drop or flow rate down such a pipe.
The L and D subscripts indicate the length scale basis for the Grashof number. The transition to turbulent flow occurs in the range 10 8 < Gr L < 10 9 for natural convection from vertical flat plates. At higher Grashof numbers, the boundary layer is turbulent; at lower Grashof numbers, the boundary layer is laminar, that is, in the range 10 3 ...