Question of Units

Question

Hi

So I'm to do an energy balance within the water body i'm simulating.

I've been using the WIND_ENERGY, SHEAR_ENERGY and MIX_ENERGY outputs commands however i haven't seen the place where the units for these outputs is stated.  

My question is twofold; what are the units for these outputs and are there other energy sources the model can output?

Cheers

David

Answer 1

Hi David these are the available energy terms for output and their units

MIX_ENERGY, Amount of TKE left after mixing that can be transported around [m2s-3]           
MIX_FRACTION, Partial mixing fraction, []         
NF_CONV, Convective time scale Partial mixing fraction, []              
NF_TURB, Turbulent time scale Partial mixing fraction, []              
ENERGY_REQ, Energy required to mix two cells (Essentially PE), [m2s-3]            
SHEAR_ENERGY, Energy generated by shear mixing, [m2s-3]          
WIND_ENERGY , Energy generated by wind mixing, [m2s-3]          
CONV_ENERGY, Energy generated by convective mixing, [m2s-3]          
BBL_ENERGY , Energy generated by benthic boundary layer mixing, [m2s-3]          
DISSIPATION, Energy dissipated, [m2s-3]

Comments

Thanks very much for the quick reply it's been every useful!

One other follow question is it possible to output the mixing energy  that come from the bubblers within the model?

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This isn't currently possible.  The bubbler mixing isn't really done as an energy budget.

We could maybe quantify the change in PE from the bubbler and add that as an output for each column.

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Thanks very much for the information

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Hello,

Apologies for replying to an old thread, but I had some follow-up questions:

1. Are the mixing energies described above specific energies rates (per unit mass of the mixed-layer)? If I recall correctly, energy rate (e.g., a Watt) has dimensions [mass][length]^2[time]^-3 .

2. When I consulted the AEM3D science manual and looked at the attributes to these variables, the units for the mixing energies above seem to be consistent with m^3/s^-2 (see below for output). If this is correct, then would the mixing energies above be an energy (e.g., a Joule) per unit area, per unit density?
Output attributes from .NC file:
SHEAR_ENERGY  [units: m^3s^-2]
WIND_ENERGY      [units: m^3s^-2]
DISSIPATION      [units: m^3s^-2]
ENERGY_REQ       [units: uknown]
MIX_ENERGY        [units: Joules]          

3. Also, when I added the keyword CONV_ENERGY into my datablock file, this particular variable was not in the output results. Is it possible the feature to output CONV_ENERGY was removed in later releases of the code? I'm am getting the following error in the command prompt:

 * WARNING * CONV_ENERGY not simulated so ignoring input in datablock file

Thank you!