Momentum balance analyzing confusion

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baipeng_up
Posts: 19
Joined: Mon Jul 22, 2013 4:54 am
Location: Ocean University of China

Momentum balance analyzing confusion

#1 Unread post by baipeng_up »

Hi ALL

Recently, I am working on the ROMS momentum balance problems, I reviewed topics about momentum balance and checked relative papers or manual, it would not work because the equation differs with each other, but I confirmed that

ubar_accel = ubar_hadv+ubar_cor+ubar_prsgrd+ubar_sstr+ubar_bstr (for example),

the momentum terms from the diagnostic outputs keeps equilibrate.

Here comes the problem that whether the momentum terms in the diagnostic file take the plus-minus sign into consideration (for example, does ubar_cor = f*vbar or ubar_cor = -1*f*vbar ?) and what are the corresponding momentum equations for the outputs in diagnostic files?

Figure 1 and 2 show the time series of u- and v-direction daily averaged 2D momentum terms for the same point, respectively(each term is of the same plus-minus sign as the diagnostic outputs). From Figure 1, there exits a negative u-direction bottom stress, combining equation 1, if we take the plus-minus sign into consideration, we would except positive u-direction bottom stress actually, however, Figure 2 shows negative v-direction Coriolis force for the same period, combing equation 2 and take the plus-minus sign into consideration as we do before, we would except positive u-direction velocity, this conflicts with the positive u-direction bottom stress...... Where do I go the wrong way?

Appreciations!
Best regards
Attachments
Figure 2, v-direction depth-averaged momentum terms
Figure 2, v-direction depth-averaged momentum terms
v.png (9.71 KiB) Viewed 2963 times
Figure 1, u-direction depth-averaged momentum terms
Figure 1, u-direction depth-averaged momentum terms
u.png (9.85 KiB) Viewed 2963 times
v-direction depth-averaged momentum equation
v-direction depth-averaged momentum equation
ve.png (2.21 KiB) Viewed 2963 times
u-direction depth-averaged momentum equation
u-direction depth-averaged momentum equation
ue.png (2.23 KiB) Viewed 2963 times

baipeng_up
Posts: 19
Joined: Mon Jul 22, 2013 4:54 am
Location: Ocean University of China

Re: Momentum balance analyzing confusion

#2 Unread post by baipeng_up »

Now I have got the answer myself, :oops: all momentum terms should have take the plus-minus sign into consideration, when one tries to make analysis, it should be consistent with the chosen momentum equation form. :D

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