[MITgcm-support] Inertial Oscillations

[Klymak Jody]

If you have a doubly periodic f plane and start with a constant u every where you will have a perfectly reasonable inertial oscillation with no other forcing. It'll decay depending on your visocosities but t should be slow relative to a plume if it's barotropic.  

If you don't want doubly periodic for some reason it should be easy to use obcs to sponge the boundaries in a time varying manner.  See my post from a couple of days ago w an example.  

Cheers.  Jody

Sent from my iPhone

> On Mar 2, 2016, at 12:15, Stroman, Ashley <acs08g at my.fsu.edu> wrote:
> 
> Hi Jody.
> 
> I am trying to look at the evolution of a vertically buoyant plume, and what the impact of inertial oscillations has on the ensuing dynamics of the plume.  The idea is to force the horizontal boundaries with a U and a V, which depend on coriolis and time to create inertial oscillations that will flow throughout the entire domain.  At least, this is the idea that I have.  Not sure if I should use two boundaries or all four horizontal boundaries.  I’m quite stuck on how to proceed with this, as I wasn’t lucky in finding anything online.
>> On Mar 2, 2016, at 3:04 PM, Klymak Jody <jklymak at uvic.ca> wrote:
>> 
>> Hi Ashely.  
>> 
>> Can you be more specific about the forcing you have in mind?  What boundary are you trying to force?  What problem are you trying to model?
>> 
>> As others said you can add forcing with obcs or rbcs.  You can also force the surface with the wind or sea level pressure.  You can also add a body force.  
>> 
>> Cheers.  Jody. 
>> 
>> Sent from my iPhone
>> 
>>> On Mar 2, 2016, at 11:52, Stroman, Ashley <acs08g at my.fsu.edu> wrote:
>>> 
>>> Hi Dustin.
>>> 
>>> That is something I haven’t considered, but I can certainly check that out.  
>>> 
>>> Ashley
>>> 
>>> 
>>>> On Mar 2, 2016, at 2:31 PM, Dustin Carroll <dcarroll at uoregon.edu> wrote:
>>>> 
>>>> Hi Ashley,
>>>> 
>>>> Wouldn’t it be simpler to compute time-dependent BC’s for u and v offline...perhaps using a simple model like in Pollard and Millard 1970? I think this is what Dimitris is suggesting here — you can use periodicExternalForcing or the EXF pkg to have the BC’s vary in time.
>>>> 
>>>> Dustin
>>>> 
>>>>> On Mar 2, 2016, at 10:58 AM, Stroman, Ashley <acs08g at my.fsu.edu> wrote:
>>>>> 
>>>>> Well, I’m quite familiar with pkg/obcs.  I’ve used Orlanski, as well as prescribe.  However, I’m more familiar with prescribing constant velocities at every time step, and not velocities that are dependent upon time and Coriolis in a more precise manner by way of inertial oscillations.  So I guess to be more specific in my original question, I’m not sure if I will need to modify the obcs_calc.F file, or if I can somehow use the “prescribe” option within pkg/obcs to set the boundary conditions for velocity which are dependent upon both time and coriolis.  I know that there is a time forcing component, but I’m just not sure how everything fits together.
>>>>> 
>>>>> Thanks. 
>>>>> Ashley Stroman
>>>>>> On Mar 1, 2016, at 3:03 PM, Dimitris Menemenlis <dmenemenlis at gmail.com> wrote:
>>>>>> 
>>>>>> Using pkg/obcs, you can force the boundaries with any velocity (and entering T/S) profiles you like.
>>>>>> 
>>>>>>> On Mar 1, 2016, at 11:21 AM, Stroman, Ashley <acs08g at my.fsu.edu> wrote:
>>>>>>> 
>>>>>>> Hello.
>>>>>>> 
>>>>>>> I am wondering if anyone has tried or knows how to force the boundary with inertial oscillations?  If this isn’t possible, then is there another way to incorporate inertial oscillations into the model? 
>>>>>>> 
>>>>>>> Thanks.
>>>>>>> Ashley Stroman
>>>>>> 
>>>>>> 
>>>>>> 
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