Search results
Results from the WOW.Com Content Network
Consider a long, thin rod of mass and length .To calculate the average linear mass density, ¯, of this one dimensional object, we can simply divide the total mass, , by the total length, : ¯ = If we describe the rod as having a varying mass (one that varies as a function of position along the length of the rod, ), we can write: = Each infinitesimal unit of mass, , is equal to the product of ...
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.
It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa ⋅ m 3 / kg , or N ⋅m/kg, which is dimensionally equivalent to m 2 /s 2 , though the latter form is rarely used.
In physics, a characteristic length is an important dimension that defines the scale of a physical system. Often, such a length is used as an input to a formula in order to predict some characteristics of the system, and it is usually required by the construction of a dimensionless quantity, in the general framework of dimensional analysis and in particular applications such as fluid mechanics.
β is the coefficient of volume expansion (equal to approximately 1/T for ideal gases) T s is the surface temperature; T ∞ is the bulk temperature; L is the vertical length; D is the diameter; ν is the kinematic viscosity. The L and D subscripts indicate the length scale basis for the Grashof number.
Using the number density of an ideal gas at 0 °C and 1 atm as a yardstick: n 0 = 1 amg = 2.686 7774 × 10 25 m −3 is often introduced as a unit of number density, for any substances at any conditions (not necessarily limited to an ideal gas at 0 °C and 1 atm).
D is the mass diffusivity (m 2 /s). μ is the dynamic viscosity of the fluid (Pa·s = N·s/m 2 = kg/m·s) ρ is the density of the fluid (kg/m 3) Pe is the Peclet Number; Re is the Reynolds Number. The heat transfer analog of the Schmidt number is the Prandtl number (Pr). The ratio of thermal diffusivity to mass diffusivity is the Lewis number ...
engineering strain, a measure of physical deformation defined as a change in length divided by the initial length. fine-structure constant, α ≈ 1/137 which characterizes the magnitude of the electromagnetic interaction between electrons. [23] β (or μ) ≈ 1836, the proton-to-electron mass ratio. This ratio is the rest mass of the proton ...