Hello, everyone
I want to calculate Lagrange residue current in a tidal bay. So I should calculate stokes velocity first. In ocean.in file, I turn on Hout(idU3Sd)=T, Hout(idV3Sd)=T (3D U/V stokes velocity), but the variables can't be written in his-file. Why? Is it because I didn't turn on some CPP? Which options should I turn on? Can someone give me some advices? Thank you very much.
How to calculate Stokes velocity
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wuting0926
- Posts: 11
- Joined: Mon Aug 19, 2013 4:37 pm
- Location: Zhejiang University
Re: How to calculate Stokes velocity
to have the stokes velocity written out, you need to activate some wave effect on currents process, such as radiation stress or vortex force. If you are using wave-current coupling, I suggest that you use the coawst model, as we have implemented vortex force method, update swan version, etc. For the currents Rutgers code, you can activate the Mellor approach.
-john
-john
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wuting0926
- Posts: 11
- Joined: Mon Aug 19, 2013 4:37 pm
- Location: Zhejiang University
Re: How to calculate Stokes velocity
Dear jcwarner,
Thank you very much for your quick reply and I apologize for my delayed apprecaition. I set #define NEARSHORE_MELLOR to act on the radiation stress but it neads Dwave in my force file. How can I get the variable? Must I use the coupling model?
Thank you very much for your quick reply and I apologize for my delayed apprecaition. I set #define NEARSHORE_MELLOR to act on the radiation stress but it neads Dwave in my force file. How can I get the variable? Must I use the coupling model?
Re: How to calculate Stokes velocity
you can use SHOREFACE as and example of how to run roms with wave input forcing file (the forcing file is listed in ocean_shoreface.in and you can edit that netcdf forcing file to see all the variables that are needed).
-- or --
you can use Inlet_test as test cases to see what the model needs to run as a coupled system of roms with swan.
in either case, if you plan to really get more involved with wave-current interaction then I suggest you use coawst modeling system. we have the most recent version of roms, but we have been updating the swan coupling and other wave-current features more in that coupled system. you can send me an email at
jcwarner@usgs.gov
to get the svn checkout of the code.
-- or --
you can use Inlet_test as test cases to see what the model needs to run as a coupled system of roms with swan.
in either case, if you plan to really get more involved with wave-current interaction then I suggest you use coawst modeling system. we have the most recent version of roms, but we have been updating the swan coupling and other wave-current features more in that coupled system. you can send me an email at
jcwarner@usgs.gov
to get the svn checkout of the code.
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wuting0926
- Posts: 11
- Joined: Mon Aug 19, 2013 4:37 pm
- Location: Zhejiang University
Re: How to calculate Stokes velocity
Dear jcwarner,
Thanks again for your warmly guidance, you really give me much help. My focus is on the Lagrange residue current to see the mass transport instead of the wave-current interaction. So I prefer to adopt the first way to get the stokes velocity. Thank you very much for your reply!
Thanks again for your warmly guidance, you really give me much help. My focus is on the Lagrange residue current to see the mass transport instead of the wave-current interaction. So I prefer to adopt the first way to get the stokes velocity. Thank you very much for your reply!
Re: How to calculate Stokes velocity
Guys, it seems you are talking about two different things 
. John, perhaps wuting0926 wants to calculate the tide-induced Stokes drift, not the wave-induced Stokes drift.
There are couple of ways to define the tide-induced Stokes drift, based on pure Lagrangian or Eulerian perspectives. As Wuting0926 wants to know the sub-tidal mass transport, it is suggested to calculate the so-called residual transport, the formula is:
Residual transport = Eulerian Transport + Stokes Transport. (#)
Residual transport is < Du > where < > is the tidal averaging operator, D is the water depth influenced by tidal elevation, u is the depth-mean velocity (a 2-D vector). Since D varies with tide, the residual transport is the sum of Eulerian transport (<D> * <u> ) and Stokes transport <D'u'>. Here D' is the tidal variation of surface elevation (i.e. the tidal elevation), u' is the tidal variation of velocity (i.e. the tidal current).
Divided by the mean water depth, the three terms in (#) are often called as the Lagrangian residual current (I don't think it is a suitable name, my preference is transport velocity), Eulerian residual current, and Stokes drift (or velocity).
I don't know if ROMS can output it directly, but obviously, you can calculate it yourself very easily.
There are many application of the tide-induced Stokes transport, but wuting0926 may refer to my paper on CSR in 2010: "Links between saltwater intrusion and subtidal circulation in the Changjiang Estuary: A model-guided study". As my research area is the Changjiang Estuary, wuting could be familiar with the processes I talked the paper.
Of course, there is another way to calculate the Stokes velocity based on the Lagrangian point of view, i.e. by tracking the particles. I don't recommend to do that, since it is highly dependent on the releasing time and hard to calculated. That is just my personal preference.
Hui Wu
. John, perhaps wuting0926 wants to calculate the tide-induced Stokes drift, not the wave-induced Stokes drift. There are couple of ways to define the tide-induced Stokes drift, based on pure Lagrangian or Eulerian perspectives. As Wuting0926 wants to know the sub-tidal mass transport, it is suggested to calculate the so-called residual transport, the formula is:
Residual transport = Eulerian Transport + Stokes Transport. (#)
Residual transport is < Du > where < > is the tidal averaging operator, D is the water depth influenced by tidal elevation, u is the depth-mean velocity (a 2-D vector). Since D varies with tide, the residual transport is the sum of Eulerian transport (<D> * <u> ) and Stokes transport <D'u'>. Here D' is the tidal variation of surface elevation (i.e. the tidal elevation), u' is the tidal variation of velocity (i.e. the tidal current).
Divided by the mean water depth, the three terms in (#) are often called as the Lagrangian residual current (I don't think it is a suitable name, my preference is transport velocity), Eulerian residual current, and Stokes drift (or velocity).
I don't know if ROMS can output it directly, but obviously, you can calculate it yourself very easily.
There are many application of the tide-induced Stokes transport, but wuting0926 may refer to my paper on CSR in 2010: "Links between saltwater intrusion and subtidal circulation in the Changjiang Estuary: A model-guided study". As my research area is the Changjiang Estuary, wuting could be familiar with the processes I talked the paper.
Of course, there is another way to calculate the Stokes velocity based on the Lagrangian point of view, i.e. by tracking the particles. I don't recommend to do that, since it is highly dependent on the releasing time and hard to calculated. That is just my personal preference.
Hui Wu
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wuting0926
- Posts: 11
- Joined: Mon Aug 19, 2013 4:37 pm
- Location: Zhejiang University
Re: How to calculate Stokes velocity
Thank you very much for your reminding. I didn't express my point clearly and mislead others. Sorry for that! Yes, I want to calculate the tide-induced stokes velocity. Maybe we can get the tide-induced stokes velocity by setting some variables to zeros(I mean no wave effect) in ROMS (just my personal guess). But it seems more conveninet to calculate the stokes drift using the formular. I will try it. Again, Thanks to all the people giving me advices.hwusklec wrote:Guys, it seems you are talking about two different things
There are couple of ways to define the tide-induced Stokes drift, based on pure Lagrangian or Eulerian perspectives. As Wuting0926 wants to know the sub-tidal mass transport, it is suggested to calculate the so-called residual transport, the formula is:
Residual transport = Eulerian Transport + Stokes Transport. (#)
Residual transport is < Du > where < > is the tidal averaging operator, D is the water depth influenced by tidal elevation, u is the depth-mean velocity (a 2-D vector). Since D varies with tide, the residual transport is the sum of Eulerian transport (<D> * <u> ) and Stokes transport <D'u'>. Here D' is the tidal variation of surface elevation (i.e. the tidal elevation), u' is the tidal variation of velocity (i.e. the tidal current).
Divided by the mean water depth, the three terms in (#) are often called as the Lagrangian residual current (I don't think it is a suitable name, my preference is transport velocity), Eulerian residual current, and Stokes drift (or velocity).
I don't know if ROMS can output it directly, but obviously, you can calculate it yourself very easily.
There are many application of the tide-induced Stokes transport, but wuting0926 may refer to my paper on CSR in 2010: "Links between saltwater intrusion and subtidal circulation in the Changjiang Estuary: A model-guided study". As my research area is the Changjiang Estuary, wuting could be familiar with the processes I talked the paper.
Of course, there is another way to calculate the Stokes velocity based on the Lagrangian point of view, i.e. by tracking the particles. I don't recommend to do that, since it is highly dependent on the releasing time and hard to calculated. That is just my personal preference.
Hui Wu