Chee2940 Lecture 7 Part B - Navier-stokes Eqs (addedum)

  • November 2019
  • PDF

This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA


Overview

Download & View Chee2940 Lecture 7 Part B - Navier-stokes Eqs (addedum) as PDF for free.

More details

  • Words: 585
  • Pages: 3
Table 7.1 Continuity and Navier-Stokes equations in the Cartesian coordinate system (x, y, z)

Continuity:

∂Wx ∂W y ∂Wz + + =0 ∂x ∂y ∂z

x–component:

∂Wx ∂Wx ∂Wx ∂Wx 1 ∂P µ + Wx + Wy + Wz =− + ∆W x ∂t ∂x ∂y ∂z δ ∂y δ

y–component:

z–component:

∂W y ∂t

+ Wx

∂W y ∂x

+ Wy

∂W y ∂y

+ Wz

∂W y ∂z

=−

1 ∂P µ + ∆W y δ ∂y δ

∂Wz ∂Wz ∂Wz ∂Wz 1 ∂P µ + Wx + Wy + Wz =− + ∆Wz ∂t ∂x ∂y ∂z δ ∂y δ

Note: The pressure in these equations also includes the hydrostatic pressure term.

where the Laplace operator is described by ∆≡

∂2 ∂2 ∂2 + + ∂x 2 ∂y 2 ∂z 2

Table 7.2 Continuity and Navier-Stokes equations in the spherical coordinate system (r, ϕ, φ)

∂ 2 r ∂ r ∂Wφ r Wr + Wϕ sin ϕ + =0 ∂r sin ϕ ∂ϕ sin ϕ ∂φ

(

Continuity:

)

(

)

r–component: Wφ ∂Wr Wϕ2 + Wφ2 ∂Wr ∂Wr Wϕ ∂Wr + Wr + + − = ∂t ∂r r ∂ϕ r sin ϕ ∂φ r −

1 ∂P µ  2 ∂Wϕ 2 ∂Wφ 2Wr 2Wϕ cot ϕ  +  ∆Wr − 2 − 2 − 2 −  δ ∂r δ  r ∂ϕ r sin ϕ ∂φ r r2 

ϕ–component: ∂Wϕ ∂t

+ Wr

∂Wϕ ∂r

+

Wϕ ∂Wϕ r

∂ϕ

+ −



∂Wϕ

r sin ϕ ∂φ

+

WrWϕ − Wφ2 cot ϕ r

=

Wϕ  1 ∂P µ  2 ∂Wr 2cos ϕ ∂Wφ +  ∆Wϕ + 2 − 2 2 − 2 2  δ r ∂ϕ δ  r ∂ϕ r sin ϕ ∂φ r sin ϕ 

φ–component: ∂Wφ ∂t

+ Wr

∂Wφ ∂r

+

Wϕ ∂Wφ r

∂ϕ

+ −



∂Wφ

r sin ϕ ∂φ

+

WφWr + WφWϕ cot ϕ r

=

2Wφ  1 ∂P µ  2 ∂Wr 2cos φ ∂Wϕ +  ∆Wφ + 2 + 2 2 − 2 2  δ r sin ϕ ∂φ δ  r sin ϕ ∂φ r sin φ ∂φ r sin ϕ 

Laplace operator: ∆≡

1 ∂ 2 ∂  1 ∂  ∂  1 ∂2 ϕ r + sin +     ∂r  r 2 sin 2 ϕ ∂φ 2 r 2 ∂r  ∂r  r 2 sin ϕ ∂ϕ 

Table 7.3 Continuity and Navier-Stokes equations in the cylindrical coordinate system (ϕ, r, z)

∂Wr 1 ∂Wϕ ∂Wz Wr + + + =0 r ∂ϕ r ∂r ∂z

Continuity:

ϕ−component:

∂Wϕ ∂t

+ Wr

∂Wϕ ∂r

+ −

r−component:

Wϕ ∂Wϕ r

∂ϕ

+ Wz

∂Wϕ ∂z

+

WrWϕ r

=

1 ∂P µ  2 ∂Wr Wϕ  +  ∆Wϕ + 2 − 2  δ r ∂ϕ δ  r ∂ϕ r 

2 ∂Wr ∂Wr Wϕ ∂Wr ∂Wr Wϕ + Wr + + Wz − = ∂t ∂r ∂z r ∂ϕ r



1 ∂P µ  2 ∂Wϕ Wr  +  ∆Wr − 2 − 2 δ ∂r δ  r ∂ϕ r 

z−component:

∂Wz ∂Wz Wϕ ∂Wz ∂Wz 1 ∂P µ + Wr + + Wz =− + ∆Wz ∂t ∂r ∂z δ ∂z δ r ∂ϕ

Laplace operator:

∆≡

∂2 1 ∂2 ∂2 1 ∂ + + + ∂r 2 r 2 ∂ϕ 2 ∂z 2 r ∂r

Related Documents