Why the result of the blending method (NWS30) is the same as the result of the GAHM (NWS20)?

[jalal-90]

Dear sir,
I am just wondering why the blending method gives the same result as the GAHM model (please see the attachment). Could you tell me the reason for this result?

I also tried with your test case that you provided here https://github.com/adcirc/adcirc-testsuite/tree/v56/adcirc/adcirc_nws30_wlcorrection. But there is no difference between the blending method and GAHM.

[jalal-90]

I am using ADCIRC v55.01

[tgasher]

There's a mistake in the test case, I think due to some differences in versions when I created it. In the meantime, for your issue with your simulation, what radii coefficients are you using in the fort.15 file and what're your RMWs?

[jalal-90]

I am a very new user of ADCIRC and just followed your test case. In the WTIMINC line, I use the following information.
2012 09 21 00 1 0.9 1 21600 100 110
YYYY,MM,DD,HH24,StormNumber,BLAdj,Geofactor,WTIMINC for gridded met,min and max rmws for blending

I did not mention the radii coefficients in the fort.15 file. How can I define them in fort.15 file? Could I have a sample fort.15 file?

My min and max RMWs are 10 and 40 respectively.

[jalal-90]

I added the radii coefficients and RMWs in the fort.15 file. But I am still getting the same result. Does it mean that ADCIRC itself has no solution?

[tgasher]

Can you post the fort.15 from your own test case? The 100 and the 110 on the example's WTIMINC line correspond to RMW multipliers that define the inner and outer limits at which blending occurs. So, you'll very likely want to use much smaller coefficients.

[jalal-90]

OceanMesh2D ! 30 CHARACTER ALPHANUM RUN DESCRIPTION
Blended GAHM & Background Wind and Pressure ! 20 CHARACTER ALPANUMERIC RUN IDENTIFICATION
1 ! NFOVER - NONFATAL ERROR OVERRIDE OPTION
0 ! NABOUT - ABREVIATED OUTPUT OPTION PARAMETER
1800 ! NSCREEN - OUTPUT TO UNIT 6 PARAMETER
0 ! IHOT - HOT START OPTION PARAMETER
2 ! ICS - COORDINATE SYSTEM OPTION PARAMETER
511112 ! IM - MODEL RUN TYPE: 0=2DDI, 1=3DL(VS), 2=3DL(DSS)
1 ! NOLIBF - NONLINEAR BOTTOM FRICTION OPTION
1 ! NOLIFA - OPTION TO INCLUDE FINITE AMPLITUDE TERMS
1 ! NOLICA - OPTION TO INCLUDE CONVECTIVE ACCELERATION TERMS
1 ! NOLICAT - OPTION TO CONSIDER TIME DERIVATIVE OF CONV ACC TERMS
0 ! NWP - VARIABLE BOTTOM FRICTION AND LATERAL VISCOSITY OPTION PARAMETER
1 ! NCOR - VARIABLE CORIOLIS IN SPACE OPTION PARAMETER
0 ! NTIP - TIDAL POTENTIAL OPTION PARAMETER
30 ! NWS - WIND STRESS AND BAROMETRIC PRESSURE OPTION PARAMETER
1 ! NRAMP - RAMP FUNCTION OPTION
9.81 ! G - ACCELERATION DUE TO GRAVITY - DETERMINES UNITS
0.005 ! TAU0 - WEIGHTING FACTOR IN GWCE
2.0 ! DT - TIME STEP (IN SECONDS)
0.0 ! STATIM - STARTING SIMULATION TIME IN DAYS
0.0 ! REFTIME - REFERENCE TIME (IN DAYS) FOR NODAL FACTORS AND EQUILIBRIUM ARGS
2012 09 21 00 1 0.9 1 21600 10 40 ! WTIMINC line YYYY,MM,DD,HH24,StormNumber,BLAdj,Geofactor,WTIMINC for gridded met,min and max rmws for blending
2.0 ! RNDAY - TOTAL LENGTH OF SIMULATION (IN DAYS)
1.0 ! DRAMP - DURATION OF RAMP FUNCTION (IN DAYS)
0 1 0 ! TIME WEIGHTING FACTORS FOR THE GWCE EQUATION
0.1 0 0 0.01 ! H0 - MINIMUM CUTOFF DEPTH
126.246187 25.248936 ! SLAM0,SFEA0 - CENTER OF CPP PROJECTION (NOT USED IF ICS=1, NTIP=0, NCOR=0)
0.0025 1.0 10. 0.33333 ! FFACTOR, HBREAK, FTHETA, FGAMMA - HYBRID NONLINEAR BOTTOM FRICTION PARAMETERS
5.0 ! ESL - LATERAL EDDY VISCOSITY COEFFICIENT; IGNORED IF NWP =1
0.00010 ! CORI - CORIOLIS PARAMETER - IGNORED IF NCOR = 1
0 ! NTIF - TOTAL NUMBER OF TIDAL POTENTIAL CONSTITUENTS BEING FORCED
0 ! NBFR - TOTAL NUMBER OF FORCING FREQUENCIES ON OPEN BOUNDARIES
90.0 ! ANGINN : INNER ANGLE THRESHOLD
0 0.0 3.0 900 ! NOUTE,TOUTSE,TOUTFE,NSPOOLE:ELEV STATION OUTPUT INFO (UNIT 61)
0 ! NSTAE - TOTAL NUMBER OF ELEVATION RECORDING STATIONS
0 0.0 3.0 900 ! NOUTV,TOUTSV,TOUTFV,NSPOOLV:VEL STATION OUTPUT INFO (UNIT 62)
0 ! NSTAV - TOTAL NUMBER OF VELOCITY RECORDING STATIONS
0 0.0 3.0 900 ! NOUTM,TOUTSM,TOUTFM,NSPOOLM:METEO STATION OUTPUT INFO (UNITS 71/72)
0 ! NSTAM - TOTAL NUMBER OF METEO RECORDING STATIONS
0 0.0 3.0 400 ! NOUTGE,TOUTSGE,TOUTFGE,NSPOOLGE : GLOBAL ELEVATION OUTPUT INFO (UNIT 63)
0 0.0 3.0 400 ! NOUTGV,TOUTSGV,TOUTFGV,NSPOOLGV : GLOBAL VELOCITY OUTPUT INFO (UNIT 64)
1 0.0 3.0 400 ! NOUTGW,TOUTSGW,TOUTFGW,NSPOOLGW : GLOBAL METEO OUTPUT INFO (UNITS 73/74)
0 ! NHARF - NUMBER OF FREQENCIES IN HARMONIC ANALYSIS
0.0 0.0 0 0.0 ! THAS,THAF,NHAINC,FMV - HARMONIC ANALYSIS PARAMETERS
0 0 0 0 ! NHASE,NHASV,NHAGE,NHAGV - CONTROL HARMONIC ANALYSIS AND OUTPUT TO UNITS 51,52,53,54
0 0 ! NHSTAR,NHSINC - HOT START FILE GENERATION PARAMETERS
1 0 1e-10 25 ! ITITER,ISLDIA,CONVCR,ITMAX - ALGEBRAIC SOLUTION PARAMETERS
OceanMesh2D
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2022-09-13 00:00:00 UTC
!-- Radii coefficients for blending wind and pressure fields ---
! The following lines specify the radii coefficients for blending.
! pureVortex and pureBackground control the transition distances.
pureVortex= 2.5 ! This means # times the RMW for pure vortex influence
pureBackground= 0.8 ! This means # times the RMW for pure background influence

[jalal-90]

I added the radii coefficients at the end of the fort.15 file (please see the above fort.15 file).

[jalal-90]

Can you post the fort.15 from your own test case? The 100 and the 110 on the example's WTIMINC line correspond to RMW multipliers that define the inner and outer limits at which blending occurs. So, you'll very likely want to use much smaller coefficients.

Hello sir, good morning. Did you get the solution for the blending method in ADCIRC? Can I have a test case?

[tgasher]

I've not yet fixed the test case, but the ADCIRC blending code itself should be working fine. I just downloaded release v55.01 and verified that the blending code appears to be present; subroutine getBlendFactor is there and it is called by subroutine getMeteorologicalForcing for abs(NWS).eq.30.

In your fort.15 file, the blending RMW multipliers are 10 and 40. When you use that fort.15 with the mesh shown in your original screenshots, do you get the identical result with NWS=30 and NWS=20? And are you sure that your background meteorological fields don't just look the same as what GAHM is producing? The wind speeds are extremely small.