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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Water engineering : Surrogate-based methods for the acceleration of high-fidelity transient simulations.
Surrogate-based methods for the acceleration of high-fidelity transient simulations.
While continued advances in supercomputing are enabling the simulation of flows of increasing size and complexity, the
presence of multiple and strongly separated timescales limits their effectiveness in addressing real-world questions of
great practical value. Recent results demonstrated that, in order to simulate all relevant time scales in long transients,
several years of continuous simulations would be necessary even on the most advanced supercomputers. In fact, when
simulating time-dependent multiphysics phenomena, the overall integration time is a function of the slowest time scale:
larger problems often imply longer integration times, thus reducing the effectiveness of such machines in simulating
transients. This work aims to develop a new time-scale decoupling algorithm, based on the use of a surrogate solution.
The physics related to the fastest time scale, which is also responsible for the highest computation cost, is decoupled or
partially decoupled. Possible surrogates involve replacing the fastest scale with a reduced-order model (e.g., POD -
Proper Orthogonal Decomposition). The methods are implemented in the DNS/LES code Nek5000 and demonstrated on
the solution of the advection-diffusion equation for the temperature where buoyancy is not present. Example cases include
the 2D flow past a cylinder and 3D channel flow (for which partial results are available). The POD methodology has
validated and tested on the three-dimensional flow in T-junctions for which Particle Image Velocimetry (PIV) data is
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Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Water engineering
Date Published : 13/08/2015
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