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Engineering LibreTexts

3.9: Nomenclature

  • Page ID
    29971
  • Aobj

    Cross section of object perpendicular to velocity direction

    m2

    Apw

    Pipe wall surface

    m2

    Ap

    Pipe cross section

    m2

    CD

    Drag coefficient

    -

    Cvs

    Spatial volumetric concentration

    -

    d

    Particle diameter

    m

    de

    Diameter smallest eddy

    m

    Dp

    Pipe diameter

    m

    f

    Fanning friction factor

    -

    Fdrag

    Drag force on object

    N

    g

    Gravitational constant 9.81 m/sec2

    m/s2

    i, il, iw

    Hydraulic gradient liquid

    m.w.c./m

    im

    Hydraulic gradient mixture

    m.w.c./m

    ΔL

    Length of pipeline

    m

    Δpl

    Pressure difference over length ΔL liquid

    kPa

    Δpm

    Pressure difference over length ΔL pseudo homogeneous mixture

    kPa

    Re

    Reynolds number of pipe flow

    -

    Stk

    Stokes number

    -

    u*

    Friction velocity

    m/s

    vls

    Line speed

    m/s

    α

    Proportionality constant

    -

    α1

    Power of line speed

    -

    α2

    Power of pipe diameter

    -

    δv

    Thickness viscous sub-layer

    m

    ε

    Roughness of pipe wall

    m

    λl

    Darcy-Weisbach friction factor liquid to wall

    -

    ρl

    Liquid density

    ton/m3

    ρm

    Mixture density

    ton/m3

    μl

    Dynamic viscosity liquid

    Pa·s

    μm

    Dynamic viscosity pseudo homogeneous mixture

    Pa·s

    μr

    Relative dynamic viscosity

    -
    \(\ v_{\mathbf{l}}\)

    Kinematic viscosity liquid

    m2/s

    \(\ v_{\mathbf{m}}\)

    Kinematic viscosity pseudo homogeneous mixture

    m2/s

    \(\ v_{\mathbf{r}}\)

    Relative kinematic viscosity

    -
    \(\ \boldsymbol{\tau}_{\mathbf{w}}\)

    Wall shear stress

    Pa