流体动量控制方程【Motion Equation】

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  • Post category:其他


流体动量控制方程

The Equation of Motion in terms of







τ












τ



控制方程通式:







ρ








D








v














v










D


t
















=








p

















τ
















τ






+


ρ








g
















g














ρ

D

v

v

D

t

=

p

τ

τ

+

ρ

g

g


1.

直角坐标系(







x


,


y




,


z












x

,

y

,

z



)

直角坐标系Cartesian coordinates (









x,y,z












x,y,z



):
NO.







ρ




(


















v






x


















t
















+





v






x





















v






x


















x
















+





v






y























v






x


















y


















+





v






z























v






x


















z




















)




=
















p













x





















[
























x



















τ










x


x









+






















y





















τ










y




x









+






















z





















τ










z




x











]




+


ρ





g








x















ρ

(

v

x

t

+

v

x

v

x

x

+

v

y

v

x

y

+

v

z

v

x

z

)

=

p

x

[

x

τ

x

x

+

y

τ

y

x

+

z

τ

z

x

]

+

ρ

g

x


1-1







ρ




(


















v






y




















t
















+





v






x





















v






y




















x
















+





v






y























v






y




















y


















+





v






z























v






y




















z




















)




=
















p













y























[
























x



















τ










x


y











+






















y





















τ










y




y











+






















z





















τ










z




y













]




+


ρ





g








y

















ρ

(

v

y

t

+

v

x

v

y

x

+

v

y

v

y

y

+

v

z

v

y

z

)

=

p

y

[

x

τ

x

y

+

y

τ

y

y

+

z

τ

z

y

]

+

ρ

g

y


1-2







ρ




(


















v






z




















t
















+





v






x





















v






z




















x
















+





v






y























v






z




















y


















+





v






z























v






z




















z




















)




=
















p













z























[
























x



















τ










x


z











+






















y





















τ










y




z











+






















z





















τ










z




z













]




+


ρ





g








z

















ρ

(

v

z

t

+

v

x

v

z

x

+

v

y

v

z

y

+

v

z

v

z

z

)

=

p

z

[

x

τ

x

z

+

y

τ

y

z

+

z

τ

z

z

]

+

ρ

g

z


1-3

2.

圆柱坐标系(







r


,


θ


,


z












r

,

θ

,

z



)

圆柱坐标系Cylindrical coordinates coordinates (










r,




θ




, z













r, 

θ

, z



):

NO.









ρ




(


















v






r


















t
















+





v






r





















v






r


















r
















+










v






θ











r





























v






r


















θ
















+





v






z























v






r


















z





























v






2






θ











r

















)




=
















p













r

























[









1






r



































r
















(


r





τ










r


r









)


+







1






r



































θ



















τ










θ


r









+






















z





















τ










z




r




















τ










θ


θ













r

















]




+


ρ





g








r



















ρ

(

v

r

t

+

v

r

v

r

r

+

v

θ

r

v

r

θ

+

v

z

v

r

z

v

θ

2

r

)

=

p

r

[

1

r

r

(

r

τ

r

r

)

+

1

r

θ

τ

θ

r

+

z

τ

z

r

τ

θ

θ

r

]

+

ρ

g

r


2-1









ρ




(


















v






θ


















t
















+





v






r





















v






θ


















r
















+










v






θ











r





























v






θ


















θ
















+





v






z























v






θ


















z


















+











v






r










v






θ












r

















)




=










1






r


























p













θ

























[









1









r






2








































r
















(





r






2










τ










r


θ









)


+







1






r



































θ



















τ










θ


θ









+






















z





















τ










z




θ









+











τ










θ


r















τ










r


θ














r

















]




+


ρ





g








θ



















ρ

(

v

θ

t

+

v

r

v

θ

r

+

v

θ

r

v

θ

θ

+

v

z

v

θ

z

+

v

r

v

θ

r

)

=

1

r

p

θ

[

1

r

2

r

(

r

2

τ

r

θ

)

+

1

r

θ

τ

θ

θ

+

z

τ

z

θ

+

τ

θ

r

τ

r

θ

r

]

+

ρ

g

θ


2-2









ρ




(


















v






z




















t
















+





v






r





















v






z




















r
















+










v






θ











r





























v






z




















θ
















+





v






z























v






z




















z




















)




=
















p













z























[









1






r



































r
















(


r





τ










z




z











)


+







1






r



































θ



















τ










θ


z











+






















z





















τ










z




z













]








+


ρ





g








z





















ρ

(

v

z

t

+

v

r

v

z

r

+

v

θ

r

v

z

θ

+

v

z

v

z

z

)

=

p

z

[

1

r

r

(

r

τ

z

z

)

+

1

r

θ

τ

θ

z

+

z

τ

z

z

]

+

ρ

g

z


2-3

3.

球坐标系(







r


,


θ


,


ϕ










r

,

θ

,

ϕ



)

球坐标系Spherical coordinates(










r,




θ




,




ϕ

















r, 

θ

ϕ



):

NO.









ρ




(


















v






r


















t
















+





v






r





















v






r


















r
















+










v






θ











r





























v






r


















θ
















+










v






ϕ












r


s


i


n


θ






























v






r


















ϕ




























v






2






θ







+





v






2






ϕ












r

















)




=
















p













r

























[









1









r






2








































r
















(





r






2










τ










r


r









)


+







1







r


s


i


n


θ




































θ
















(





τ










θ


r









s


i


n


θ


)


+







1







r


s


i


n


θ




































ϕ



















τ










ϕ


r





















τ










θ


θ









+





τ










ϕ


ϕ














r

















]




+


ρ





g








r



















ρ

(

v

r

t

+

v

r

v

r

r

+

v

θ

r

v

r

θ

+

v

ϕ

r

s

i

n

θ

v

r

ϕ

v

θ

2

+

v

ϕ

2

r

)

=

p

r

[

1

r

2

r

(

r

2

τ

r

r

)

+

1

r

s

i

n

θ

θ

(

τ

θ

r

s

i

n

θ

)

+

1

r

s

i

n

θ

ϕ

τ

ϕ

r

τ

θ

θ

+

τ

ϕ

ϕ

r

]

+

ρ

g

r


3-1









ρ




(


















v






θ


















t
















+





v






r





















v






θ


















r
















+










v






θ











r





























v






θ


















θ
















+










v






ϕ












r


s


i


n


θ






























v






θ


















ϕ
















+











v






r










v






θ













v






2






ϕ







c


o


t


θ







r

















)




=










1






r


























p













θ

























[









1









r






3








































r
















(





r






3










τ










r


θ









)


+







1







r


s


i


n


θ




































θ
















(





τ










θ


θ









s


i


n


θ


)


+







1







r


s


i


n


θ




































ϕ



















τ










ϕ


θ









+








(





τ










θ


r















τ










r


θ









)








τ










ϕ


ϕ









c


o


t


θ







r

















]




+


ρ





g








θ



















ρ

(

v

θ

t

+

v

r

v

θ

r

+

v

θ

r

v

θ

θ

+

v

ϕ

r

s

i

n

θ

v

θ

ϕ

+

v

r

v

θ

v

ϕ

2

c

o

t

θ

r

)

=

1

r

p

θ

[

1

r

3

r

(

r

3

τ

r

θ

)

+

1

r

s

i

n

θ

θ

(

τ

θ

θ

s

i

n

θ

)

+

1

r

s

i

n

θ

ϕ

τ

ϕ

θ

+

(

τ

θ

r

τ

r

θ

)

τ

ϕ

ϕ

c

o

t

θ

r

]

+

ρ

g

θ


3-2









ρ




(


















v






ϕ


















t
















+





v






r





















v






ϕ


















r
















+










v






θ











r





























v






ϕ


















θ
















+










v






ϕ












r


s


i


n


θ






























v






ϕ


















ϕ
















+











v






ϕ










v






r







+





v






θ










v






ϕ







c


o


t


θ







r

















)




=










1







r


s


i


n


θ



























p













ϕ

























[









1









r






3








































r
















(





r






3










τ










r


ϕ









)


+







1







r


s


i


n


θ




































θ
















(





τ










θ


ϕ









s


i


n


θ


)


+







1







r


s


i


n


θ




































ϕ



















τ










ϕ


ϕ









+








(





τ










ϕ


r















τ










r


ϕ









)


+





τ










ϕ


θ









c


o


t


θ







r

















]




+


ρ





g








ϕ



















ρ

(

v

ϕ

t

+

v

r

v

ϕ

r

+

v

θ

r

v

ϕ

θ

+

v

ϕ

r

s

i

n

θ

v

ϕ

ϕ

+

v

ϕ

v

r

+

v

θ

v

ϕ

c

o

t

θ

r

)

=

1

r

s

i

n

θ

p

ϕ

[

1

r

3

r

(

r

3

τ

r

ϕ

)

+

1

r

s

i

n

θ

θ

(

τ

θ

ϕ

s

i

n

θ

)

+

1

r

s

i

n

θ

ϕ

τ

ϕ

ϕ

+

(

τ

ϕ

r

τ

r

ϕ

)

+

τ

ϕ

θ

c

o

t

θ

r

]

+

ρ

g

ϕ


3-3

注:如果













τ
















τ














τ

τ



具有对称性,那么










τ










r


θ















τ










θ


r









=


0










τ

r

θ

τ

θ

r

=

0



参考文献

  1. R. Byron Bird, Warren E. stewart, Edwin N. Lightfoot.* Transport phenomena:Revised second edition* John Wiely &Sons, Inc.



版权声明:本文为ChemToMath原创文章,遵循 CC 4.0 BY-SA 版权协议,转载请附上原文出处链接和本声明。