Name | Last modified | Size | Description | |
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Parent Directory | - | |||

re180/ | 2011-06-20 13:46 | - | ||

re550/ | 2011-06-20 13:48 | - | ||

re950/ | 2011-06-20 14:04 | - | ||

------------------------------------------------------------------------------ ----------- FORMAT OF THE FIELD FILES -------------- ------------------------------------------------------------------------------ The files are written in standard FORTRAN-UNFORMATTED format, the endianness of the bytes is BIG (least significant bit comes first). The file contains three records: RECORD #1: SOME PARAMETERS time,Re,alp,bet,a0,mx,my,mz time (real, 4 bytes): Cumulative time of the simulation in the field (it should be something around four thousand for the retau=550 field). !!!! PLEASE NOTE THAT IN THE CASE RE=950, time is a real*8 !!!! Re (real, 4bytes): Inverse of the viscosity used in the code, which defines the scaling in which the code works. The channel half-width is h=!, but Re is not the bulk Reynolds number, because the bulk velocity is not one (it is about 0.89, but you can integrate it exactly from the mean profiles, using the values of utau in the master README). (It should be Re=11180 for retau=550). alp (real, 4 bytes): Defines the streamwise periodicity Lx of the box as Lx=2*pi/alp (it should be 0.25 for the retau=550 field). In the present notation, the streamwise wavenumber of the i-th Fourier mode of a variable is kx=alp*i, i=0,...,mx/2-1. bet (real, 4 bytes): Defines the spanwise periodicity Lz of the box as Lz=2*pi/bet (it should be 0.50 for the retau=550 field). In the present notation, the spanwise wavenumber of the k-th Fourier mode of a variable is kz=k*bet, k= 0,...,(mz-1)/2,(mz-1)/2,......, -1 a0 (real, 4bytes): Horizontal velocity of the Galilean reference frame (it should be 0 or 0.53) mx (int, 4bytes): Twice the number of Fourier Gallerkin modes in x. my (int, 4bytes): Number of Chebychev modes in y. mz (int, 4bytes): Number of Fourier Gallerkin modes in z. We use the 2/3 dealiasing rule in x and z, so the number of collocation points in those directions are 3/2 times the number of Gallerkin modes, and the extra modes are padded with zeroes. RECORD #2: 00-MODES (u00(j),w00(j),j=1,my) u00(j) and w00(j) (real, 4bytes) are respectively the modes of the streamwise and spanwise velocity associated to zero streamwise and spanwise wavenumbers (infinite wavelengths), and to the j-th Chevychev polynomial. RECORD #3: OMEGA_Y AND PHI=NABLA^2(V) ((vor(i,k,j),phi(i,k,j),i=1,mx),k=1,mz) vor and phi are 4 bytes real arrays, and cmplx(vor(2*i-1,k,j),vor(2*i,k,j)) and cmplx(phi(2*i-1,k,j),phi(2*i,k,j)) are respectively the i-th and k-th complex Fourier coefficients of omega_y and phi associated to the j-th Chevychev polynomial. This formulation is the same of Kim, Moin and Moser, (1987), Journal of Fluid Mechanics vol 177, pp 133-166 The fields were written using a procedure similar to the following one: c----------------------------------------------------------------------- subroutine escribe(mx,my,mz,time,Re,alp,bet,a0,u00,w00,vor,phi) integer i,j,k,mx,my,mz real time,Re,alp,bet,a0,u00(my),w00(my),vor(mx,mz,my), & phi(mx,mz,my) open (20,file='field',status='unknown',form='unformatted') rewind(20) write(20) time,Re,alp,bet,a0,mx,my,mz write(20) (u00(j),w00(j),j=1,my) do j=1,my write(20) ((vor(i,k,j),phi(i,k,j),i=1,mx),k=1,mz) enddo close(20) end c----------------------------------------------------------------------- ------------------------------------------------------------------------------ For doubts about the format of the file :: juanc@torroja.dmt.upm.es ---------------------------------------- WARNING: THIS AREA IS UNDER CONSTRUCTION ---------------------------------------- last touched: 02-18-2004