# Contents of /trunk/modellib/py_src/temperature.py

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Thu Mar 23 02:27:57 2006 UTC (15 years, 1 month ago) by elspeth
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 1 # $Id$ 2 3 __copyright__=""" Copyright (c) 2006 by ACcESS MNRF 4 5 Primary Business: Queensland, Australia""" 6 __license__="""Licensed under the Open Software License version 3.0 7 8 9 from esys.escript import * 10 from esys.escript.modelframe import Model,IterationDivergenceError 11 from esys.escript.linearPDEs import AdvectivePDE,LinearPDE 12 import numarray 13 14 15 class TemperatureAdvection(Model): 16 """ 17 18 The conservation of internal heat energy is given by 19 20 M{S{rho} c_p ( dT/dt+v[j]*grad(T)[j])-grad(\kappa grad(T)_{,i}=Q} 21 22 M{n_i\kappa T_{,i}=0} 23 24 it is assummed that M{\rho c_p} is constant in time. 25 26 solved by Taylor Galerkin method 27 28 """ 29 def __init__(self,debug=False): 30 Model.__init__(self,debug=debug) 31 self.declareParameter(domain=None, \ 32 temperature=1., \ 33 velocity=numarray.zeros([3]), 34 density=1., \ 35 heat_capacity=1., \ 36 thermal_permabilty=1., \ 37 # reference_temperature=0., \ 38 # radiation_coefficient=0., \ 39 thermal_source=0., \ 40 fixed_temperature=0., 41 location_fixed_temperature=Data(), 42 safety_factor=0.1) 43 44 def doInitialization(self): 45 self.__pde=LinearPDE(self.domain) 46 self.__pde.setSymmetryOn() 47 self.__pde.setReducedOrderOn() 48 self.__pde.setSolverMethod(self.__pde.LUMPING) 49 self.__pde.setValue(D=self.heat_capacity*self.density) 50 51 def getSafeTimeStepSize(self,dt): 52 """ 53 returns new step size 54 """ 55 h=self.domain.getSize() 56 return self.safety_factor*inf(h**2/(h*abs(self.heat_capacity*self.density)*length(self.velocity)+self.thermal_permabilty)) 57 58 def G(self,T,alpha): 59 """ 60 tangential operator for taylor galerikin 61 """ 62 g=grad(T) 63 self.__pde.setValue(X=-self.thermal_permabilty*g, \ 64 Y=self.thermal_source-self.__rhocp*inner(self.velocity,g), \ 65 r=(self.__fixed_T-self.temperature)*alpha,\ 66 q=self.location_fixed_temperature) 67 return self.__pde.getSolution() 68 69 70 def doStepPostprocessing(self,dt): 71 """ 72 perform taylor galerkin step 73 """ 74 T=self.temperature 75 self.__rhocp=self.heat_capacity*self.density 76 self.__fixed_T=self.fixed_temperature 77 self.temperature=dt*self.G(dt/2*self.G(T,1./dt)+T,1./dt)+T 78 self.trace("Temperature range is %e %e"%(inf(self.temperature),sup(self.temperature)))