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C.1 Magnetic Field Data Format

The external magnetic field data file is in text format and of the following structure:


$MAG\_DATA$          
$nX$ $nY$ $nZ$      
$X1$ $Xn$        
$Y1$ $Yn$        
$Z1$ $Zn$        
$nAC$ $Freq$        
$BX_{re-1}$ $BY_{re-1}$ $BZ_{re-1}$ $BX_{im-1}$ $BY_{im-1}$ $BZ_{im-1}$
...          
$BX_{re-n}$ $BY_{re-n}$ $BZ_{re-n}$ $BX_{im-n}$ $BY_{im-n}$ $BZ_{im-n}$

The first line is an identification tag for the data file. The second line defines the number of data points in the $\it {x}$, $\it {y}$ and $\it {z}$ directions. The next three lines define the ranges in $\it {x}$, $\it {y}$ and $\it {z}$ directions. The data points are assumed to be evenly distributed along each direction. Line 6 defines the AC field flag and frequency. When nAC = 0, the magnetic field is static. For AC field, nAC = 1 and Freq is the frequency in Hz.

The rest of the data file contains the magnetic field data points. Each line defines the components of the real and imaginary parts of the magnetic field vector on one data point. The data points are indexed as:


$\displaystyle \it {l}=\it {i}+\it {nX}((\it {j}-1)+\it {nY}(\it {k}-1))$      
$\displaystyle \it {i}=1,...,\it {nX}; \it {j}=1,...,\it {nY}; \it {k}=1,...,\it {nZ}$      

The data is listed in the ascending order from 1 to $\it {n}$, where $\it {n}$ is the total number of data points given by $\it {n}$ = $\it {nX}$ $\it {nY}$ $\it {nZ}$.

For magnetic fields comprised of both DC and AC fields, the entire file structure described above is repeated for the DC and AC parts. These two sections within the same file will be imported into FLUENT and stored separately. The order of the DC and AC sections of the file is not important.

The imported data is interpreted as a snapshot of the applied magnetic field at an instant in time. Complex form is used to accommodate oscillating/moving fields. Thus, using complex numbers, and with reference to the quantities defined in Appendix  B,


$\displaystyle \vec{B_0}$ $\textstyle \equiv$ $\displaystyle \left\{ \begin{array}{cc} \it {BX}_{re} \\ \it {BY}_{re} \\ \it... ...rray}{cc} \it {BX}_{im} \\ \it {BY}_{im} \\ \it {BZ}_{im} \end{array}\right\}$  
  $\textstyle =$ $\displaystyle \it {\bar{B}_0}+\it {A_0}exp[\it {i}(2\pi\it {ft}+\phi)]$ (C.1-1)

For a DC field,


 \it {\bar{B}_{o,i}}=\it {B_{re,i}} \qquad \it {i=x,y,z} (C.1-2)

For an AC field,


 \it {A_{o,i}}=\sqrt{\it {B_{re,i}}^2 + \it {B_{im,i}}^2} \qquad \it {i=x,y,z} (C.1-3)

and


 \it {\phi_i}=\it {tg}^{-1}\biggl(\frac{\it {B_{im,i}}}{\it {B_{re,i}}}\biggr) \qquad \it {i=x,y,z} (C.1-4)

Note that when the external magnetic field import option is used, the frequency, $\it {f}$, read from this file supercedes the value specified in the GUI.


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© Fluent Inc. 2006-06-21