How to set the water density using EE?

EFDC_Explorer
1

Dear EE users,

I am studying about the density current flow at the moment. I have looked to the the density testing cased entitled “2.5_2D-Tank_Density_Flow_Test_Case” but i could not find the way to assign the high water density for the salinity water. Your advice is highly appreciated.

Cheers,
Mohamed

2

Hello Mohammad,

In EFDC model, density is computed as a function of salinity and temperature if you are interested in hydrodynamics. So, in order to see the changes in density of water, you will need to turn on either salinity module or temperature module. In the tank example you will find that the initial condition has half salt water and half fresh water. So, as the fresh water and salt water tend to mix, the density of the water would change. The profile of density would look similar to the profile of salinity. So, important thing to note is to turn on either temperature module or salinity module if you want to see the density variation.

If you are familar with the EFDC code, then please refer to subroutine calbuoy.f90 where density is computed. For example, if both salinity and temperature are activated, density is computed as follows (section of code from calbuoy.f90): 


	! *** CASE: BOTH SALINITY AND TEMPERATURE
	      DO K=1,KC  
	        DO LP=1,LLWET(K,ND)
	          L=LKWET(LP,K,ND)  
	          SSTMP=MAX(SAL(L,K),0.)  
	          TTMP=TEM(L,K)  
	          RHTMP = 999.842594 + 6.793952D-2TTMP - 9.095290D-3TTMPTTMP + 1.001685D-4TTMPTTMPTTMP - 1.120083D-6TTMPTTMPTTMPTTMP + 6.536332D-9TTMPTTMPTTMPTTMPTTMP 
	          RHO1= RHTMP+SSTMP(0.824493 - 4.0899D-3TTMP + 7.6438D-5TTMPTTMP - 8.2467D-7TTMPTTMPTTMP + 5.3875D-9TTMPTTMPTTMPTTMP) &
	                      +SQRT(SSTMP)SSTMP(-5.72466D-3+1.0227D-4TTMP - 1.6546D-6TTMPTTMP) + 4.8314D-4SSTMP*SSTMP  
	          RHOW(L,K) = RHO1
	
	          ! *** REPLACE DENSITY B(L,K) WITH BUOYANCY B(L,K)  
	          B(L,K)=(RHO1/RHOO)-1._8  
	        ENDDO  
	      ENDDO

3

Hi,

Thank you for your reply.

This is exactly what I want to look at. But i still wondering can we use the EE to assign the initial saline water density different as same as in the testcase?

Cheers,
Mohamed

4

Please refer to the guidance here and let us know if it doesn’t answer your question: https://eemodelingsystem.atlassian.net/wiki/spaces/HOW/pages/2391954/Setting+Initial+Conditions+for+Water+Column+Constituents