Joshua Hope-Collins
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View article: Data assimilation using a global Girsanov nudged particle filter
Data assimilation using a global Girsanov nudged particle filter Open
We present a particle filtering algorithm for stochastic models on infinite dimensional state space, making use of Girsanov perturbations to nudge the ensemble of particles into regions of higher likelihood. We argue that the optimal contr…
View article: asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond
asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond Open
Modern high-performance computers are massively parallel; for many partial differential equation applications spatial parallelism saturates long before the computer's capability is reached. Parallel-in-time methods enable further speedup b…
View article: Data assimilation using a global Girsanov nudged particle filter
Data assimilation using a global Girsanov nudged particle filter Open
We present a particle filtering algorithm for stochastic models on infinite dimensional state space, making use of Girsanov perturbations to nudge the ensemble of particles into regions of higher likelihood. We argue that the optimal contr…
View article: asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond
asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond Open
Modern high performance computers are massively parallel; for many PDE applications spatial parallelism saturates long before the computer's capability is reached. Parallel-in-time methods enable further speedup beyond spatial saturation b…
View article: Artificial diffusion for convective and acoustic low Mach number flows II: Application to Liou-Steffen, Zha-Bilgen and Toro-Vasquez convection-pressure flux splittings
Artificial diffusion for convective and acoustic low Mach number flows II: Application to Liou-Steffen, Zha-Bilgen and Toro-Vasquez convection-pressure flux splittings Open
Liou-Steffen splitting (AUSM) schemes are popular for low Mach number simulations, however, like many numerical schemes for compressible flow they require careful modification to accurately resolve convective features in this regime. Previ…
View article: Parallel-in-time solution of finite element atmospheric models using ParaDiag
Parallel-in-time solution of finite element atmospheric models using ParaDiag Open
Modern numerical weather prediction requires vast amounts of computing power, so highly scalable algorithms are essential on massively parallel modern hardware. However, once the strong scaling limit is reached for spatial parallelism, the…
View article: Artificial Diffusion for Convective and Acoustic Low Mach Number Flows Ii: Application to Liou-Steffen, Zha-Bilgen and Toro-Vasquez Convection-Pressure Flux Splittings
Artificial Diffusion for Convective and Acoustic Low Mach Number Flows Ii: Application to Liou-Steffen, Zha-Bilgen and Toro-Vasquez Convection-Pressure Flux Splittings Open
View article: Artificial diffusion for convective and acoustic low Mach number flows I: Analysis of the modified equations, and application to Roe-type schemes
Artificial diffusion for convective and acoustic low Mach number flows I: Analysis of the modified equations, and application to Roe-type schemes Open
Three asymptotic limits exist for the Euler equations at low Mach number - purely convective, purely acoustic, and mixed convective-acoustic. Standard collocated density-based numerical schemes for compressible flow are known to fail at lo…
View article: Generation of turbulent inflow data from realistic approximations of the covariance tensor
Generation of turbulent inflow data from realistic approximations of the covariance tensor Open
This study presents a novel synthetic inflow generator capable of producing a random field matching a realistic set of two-point statistics with minimal input. The method is based on two main elements. The first element is a procedure to i…
View article: Artificial Diffusion for Convective and Acoustic Low Mach Number Flows I: Analysis of the Modified Equations, and Application to Roe-Type Schemes
Artificial Diffusion for Convective and Acoustic Low Mach Number Flows I: Analysis of the Modified Equations, and Application to Roe-Type Schemes Open