Karthik Duraisamy

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Heterogeneous computers with processors and accelerators are becoming widespread in scientific computing. However, it is difficult to program hybrid architectures and there is no commonly accepted programming model. Ideally, applications should be written in a way that is portable to many platforms, but providing this portability for general programs is a(More)
We demonstrate an adjoint based approach for accelerating Monte Carlo estimation of risk, and apply it to estimating the probability of unstart in a SCRamjet engine under uncertain conditions that are characterized by various Gaussian and non-Gaussian distributions. The adjoint equation is solved with respect to an objective function that is used to(More)
Transonic flows on the advancing side of a helicopter rotor and blade–wake/blade– vortex interactions (BWI, BVI) are the major sources of helicopter noise. Both phenomena should be accurately predicted for a successful improvement of state-of-the-art helicopter design. To account for the former, a fully compressible CFD solver is essential in computing the(More)
Standard Gaussian Process (GP) regression, a powerful machine learning tool, is computationally expensive when it is applied to large datasets, and potentially inaccurate when data points are sparsely distributed in a highdimensional feature space. To address these challenges, a new multiscale, sparsified GP algorithm is formulated, with the goal of(More)
Adjoint methods are widely used in various areas of computational science to efficiently obtain sensitivities of functionals which result from the solution of partial differential equations (PDEs). In addition, adjoint methods have been used in other settings including error estimation, uncertainty quantification and inverse problem formulations. When(More)
Central to the computation of helicopter blade noise is the accurate prediction of blade-wake interaction (BWI) and blade-vortex interaction (BVI) surrounding the rotor. Numerical discretization errors in the wake region have to be minimized in order to capture the vortex evolution with high fidelity. In particular, artificial dissipation introduced in the(More)
We use retrospective cost adaptive control (RCAC) to control the thrust generated by a scramjet. A quasi-one-dimensional version of the mass, momentum, and energy conservation equations of compressible fluid flow with heat release is used to model the physics of the scramjet. First, we study the dynamic behavior of the scramjet model. Then, we apply system(More)
The use of a shroud around the rotor of a wind turbine has been known to augment the airflow through the rotor plane and hence result in improved performance. This work uses Computational Fluid Dynamics (CFD) to assess the validity of several simple theories which attempt to extend Betz theory to shrouded turbines. Two CFD models are employed and compared(More)
Karthik Duraisamy Assistant Professor, Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48104 Abstract A modeling paradigm is developed to augment predictive models of turbulence by effectively utilizing limited data generated from physical experiments. The key components of our approach involve inverse modeling to infer the(More)