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Optimization of neutron energy-group structure in thermal lattices using ultrafine bilinear adjoint function
, Article Progress in Nuclear Energy ; Volume 85 , 2015 , Pages 648-658 ; 01491970 (ISSN) ; Salehi, A. A ; Vosoughi, N ; Akbari, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
To solve neutron transport equation in multigroup approach, in addition to weighting function and number of energy groups, proper selection of the group boundaries have high importance for the accuracy of the calculations. In the current paper, the bilinear combination of forward and adjoint neutron spectra is used for the optimization of 69 energy group structure of WIMSD5 lattice physics code. To remedy the energy self-shielding effect, homogeneous adjoint and forward BN equations on an ultrafine energy group structure have been solved to obtain the ultrafine forward and adjoint spectra. The coarse group intervals are selected to have equal values of bilinear function in each...
Aerodynamic shape optimization using a morphing-body optimization method
, Article 13th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference 2010, 13 September 2010 through 15 September 2010, Ft. Worth, TX ; 2010 ; 9781600869549 (ISBN) ; Mazaheri, K ; Sharif University of Technology
2010
Abstract
A morphing-body optimization method is introduced to accelerate adjoint-based shape optimization techniques. The optimization process solves the flow and adjoint equations around a continuously deforming body whose shape is controlled by the cost function. Effect of various parameters on the efficiency of the scheme is studied. It is found that, for the best performance of the algorithm, the morphing rate of the airfoil should be restricted, since larger rates foster oscillations and lower values are not computationally feasible. Moreover, the iterative procedure in the adjoint solver should be adapted to the iteration scheme in the flow solver and to the morphing rate
On cylindrical graph construction and its applications
, Article Electronic Journal of Combinatorics ; Volume 23, Issue 1 , 2016 ; 10778926 (ISSN) ; Hejrati, M ; Madani, M ; Sharif University of Technology
Australian National University
2016
Abstract
In this article we introduce the cylindrical construction, as an edge-replacement procedure admitting twists on both ends of the hyperedges, generalizing the concepts of lifts and Pultr templates at the same time. We prove a tensor-hom duality for this construction and we show that not only a large number of well-known graph constructions are cylindrical but also the construction and its dual give rise to some new graph constructions, applications and results. To show the applicability of the main duality we introduce generalized Grötzsch, generalized Petersen-like and Coxeter-like graphs and we prove some coloring properties of these graphs
Optimization of the direct discrete method using the solution of the adjoint equation and its application in the multi-group neutron diffusion equation
, Article AIP Conference Proceedings ; Volume 1389 , 2011 , Pages 1777-1781 ; 0094243X (ISSN) ; 9780735409569 (ISBN) ; Vosoughi, N ; Sharif University of Technology
2011
Abstract
Obtaining the set of algebraic equations that directly correspond to a physical phenomenon has been viable in the recent direct discrete method (DDM). Although this method may find its roots in physical and geometrical considerations, there are still some degrees of freedom that one may suspect optimize-able. Here we have used the information embedded in the corresponding adjoint equation to form a local functional, which in turn by its minimization, yield suitable dual mesh positioning