TY - GEN

T1 - Development of the adaptive collision source (ACS) method for discrete ordinates

AU - Walters, William J.

AU - Haghighat, Alireza

PY - 2013

Y1 - 2013

N2 - We have developed a new collision source method to solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. The angular adaptation method is unique in that the flux from each scattering source iteration is obtained, with potentially a different quadrature order. Traditionally, the flux from every iteration is combined, with the same quadrature applied to the combined flux. Since the scattering process tends to distribute the radiation more evenly over angles (i.e., make it more isotropic), the quadrature requirements generally decrease with each iteration. This allows for an optimal use of processing power, by using a high order quadrature for the first few iterations that need it, before shifting to lower order quadratures for the remaining iterations. This is essentially an extension of the first collision source method, and we call it the adaptive collision source method (ACS). The ACS methodology has been implemented in the TITAN discrete ordinates code, and has shown a relative speedup of 1.5-2.5 on a test problem, for the same desired level of accuracy.

AB - We have developed a new collision source method to solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. The angular adaptation method is unique in that the flux from each scattering source iteration is obtained, with potentially a different quadrature order. Traditionally, the flux from every iteration is combined, with the same quadrature applied to the combined flux. Since the scattering process tends to distribute the radiation more evenly over angles (i.e., make it more isotropic), the quadrature requirements generally decrease with each iteration. This allows for an optimal use of processing power, by using a high order quadrature for the first few iterations that need it, before shifting to lower order quadratures for the remaining iterations. This is essentially an extension of the first collision source method, and we call it the adaptive collision source method (ACS). The ACS methodology has been implemented in the TITAN discrete ordinates code, and has shown a relative speedup of 1.5-2.5 on a test problem, for the same desired level of accuracy.

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M3 - Conference contribution

AN - SCOPUS:84883350538

SN - 9781627486439

T3 - International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2013

SP - 2339

EP - 2349

BT - International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2013

T2 - International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2013

Y2 - 5 May 2013 through 9 May 2013

ER -