Friction loss is significant in short pipe

[foo9008]

Homework Statement

i was told that the friction loss is significant in short pipe , but not so significant in long pipe . However , the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?

Homework Equations

The Attempt at a Solution

 

[SteamKing]

Homework Statement

i was told that the friction loss is significant in short pipe , but not so significant in long pipe . However , the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?

Homework Equations

The Attempt at a Solution

I wouldn't always be so credulous of what "somebody" tells you. Friction loss depends not only on L/D, but also V.

 

[foo9008]

I wouldn't always be so credulous of what "somebody" tells you. Friction loss depends not only on L/D, but also V.

it was written in a book ... why the friction loss due to entrance effect is significant in short pipe , but not so significant in long pipe ?

 

[SteamKing]

it was written in a book ... why the friction loss due to entrance effect is significant in short pipe , but not so significant in long pipe ?

Well, why do you think this situation would be so?

What is the relative loss due to entrance effect compared with the loss in a section of straight pipe?

Note: Your original post mentioned only friction losses. Now, you are talking about losses due to entrance effects. It's important to disclose all information at the start of a discussion to prevent misunderstandings.

 

[foo9008]

Well, why do you think this situation would be so?

What is the relative loss due to entrance effect compared with the loss in a section of straight pipe?

Note: Your original post mentioned only friction losses. Now, you are talking about losses due to entrance effects. It's important to disclose all information at the start of a discussion to prevent misunderstandings.

sorry , i mean friction due to entrance effect . why it is negligible in long pipe ? the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?

 

[SteamKing]

sorry , i mean friction due to entrance effect . why it is negligible in long pipe ? the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?

So, if the friction loss in a long pipe is relatively large, what about the ratio of the entrance loss to the friction loss in the long pipe? Is it a large ratio or a small ratio?
Is the entrance loss affected by the length of the pipe to which it is applied?

 

[foo9008]

So, if the friction loss in a long pipe is relatively large, what about the ratio of the entrance loss to the friction loss in the long pipe? Is it a large ratio or a small ratio?
Is the entrance loss affected by the length of the pipe to which it is applied?

if the friction loss in a long pipe is relatively large, the ratio of the entrance loss to the friction loss in the long pipe woul be small , ?
due to this reason , the friction loss due to entrance effect is negligible ?

 

[SteamKing]

if the friction loss in a long pipe is relatively large, the ratio of the entrance loss to the friction loss in the long pipe woul be small , ?
due to this reason , the friction loss due to entrance effect is negligible ?

In a long pipe.

How would the friction loss due to the entrance effect compare to the friction loss in a short pipe?

 

[foo9008]

In a long pipe.

How would the friction loss due to the entrance effect compare to the friction loss in a short pipe?

the friction loss in short pipe is small , so the friction due to entrance effect is significant in short pipe compared to the friction loss in short pipe?

 

[SteamKing]

the friction loss in short pipe is small , so the friction due to entrance effect is significant in short pipe compared to the friction loss in short pipe?

Yes.