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docs:utils:randomfield [2009/04/01 08:30]
gibson
docs:utils:randomfield [2010/02/02 07:55] (current)
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   <​fieldname> ​ (trailing arg 1)                        output file   <​fieldname> ​ (trailing arg 1)                        output file
 </​code>​ </​code>​
- 
 ===== mathematics ===== ===== mathematics =====
  
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 <​latex>​ <​latex>​
-u_{jklm} = (\text{random # in }[-1, 1]) * \text{smoothness}^{|l| + |j| + |k|}+u_{jklm} = (\text{random # in }[-1, 1]) * \text{(1-smoothness)}^{|l| + |j| + |k|}
 </​latex>​ </​latex>​
  
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 The form of spectral decay chosen is crude, but normally what is needed in a random field is that  The form of spectral decay chosen is crude, but normally what is needed in a random field is that 
-it meets the BCs and zero-div, is controllably smooth, and excites modes with all symmetries. ​+it meets the BCs and zero-div, is controllably smooth, and excites modes with all symmetries. It would probably be better to work the length scales Lx,Ly,Lz into the exponent of ''​(1-smoothness)'',​ so that the variations in the random field are roughly spatially isotropic
  
  
  
  
docs/utils/randomfield.1238599825.txt.gz ยท Last modified: 2009/04/01 08:30 by gibson