5 papers · 1 filter
Data Assimilation with Sparse Observations
Nan Jiang, William Layton, Nanda Nechingal Raghunathan +1
Data assimilation by nudging (also called CDA) yields exponentially decaying errors and an infinite predictability horizon if the method parameter is large enough and the observati…
Energy dissipation rates of ensemble eddy viscosity models of turbulence: the periodic box
William Layton, Nanda Nechingal Raghunathan
Classical eddy viscosity models of turbulence add an eddy viscosity term based on the Kolmogorov-Prandtl parameterization by a turbulent length scale and a turbulent kinetic en…
Modular data assimilation for flow prediction
Aytekin Çıbık, Rui Fang, William Layton
This report develops several modular, 2-step realizations (inspired by Kalman filter algorithms) of nudging-based data assimilation $$Step \ 1 \quad \frac{\widetilde {v}^{n+1}-v^{n…
The Ramshaw-Mesina Hybrid Algorithm applied to the Navier Stokes Equations
Aytekin Çibik, Farjana Siddiqua, William Layton
In 1991, Ramshaw and Mesina proposed a novel synthesis of penalty methods and artificial compression methods. When the two were balanced they found the combination was 3-4 orders m…
Convergence of a Ramshaw-Mesina Iteration
Aytekin Çibik, William Layton
In 1991 Ramshaw and Mesina introduced a clever synthesis of penalty methods and artificial compression methods. Its form makes it an interesting option to replace the pressure upda…