phishing emails - ALGORITMY 2024

An H(div)-Conforming E-HDG Method for the Incompressible Resistive MHD equations

Incompressible Magnetohydrodynamics (MHD) models are relevant in low Lundquist number liquid metals, high Lundquist number, large guide field fusion plasmas, and low Mach number compressible flows. Due to its complexity, it is crucial to understand the dynamics of electrically conducting flow in the presence of electromagnetic fields via simulation. In this work, we proposed an Embedded-hybridized discontinuous Galerkin (E-HDG) method for solving the incompressible resistive MHD equations.

In particular, the E-HDG method is computationally cheaper than the corresponding HDG method. The benefit is even significant in the three-dimensional scenario. Furthermore, a specific choice of the approximation spaces guarantees that the proposed method is H(div)-conforming, meaning that the velocity and magnetic fields are pointwise divergence-free. We implement our approach in the open-source library MFEM and validate our method using manufactured solutions. The results indicate that convergence rates in the L^2 norm for the velocity and magnetic fields are optimal, and divergence error can be reduced to machine zero. Furthermore, the proposed E-HDG discretization is pressure robust.

Simulations of supersonic flows to study trajectories of aerosols and the impaction-based sampling efficiency on a rocket-borne particle collector

This investigation applies computational fluid dynamics simulations to support the design development of an impaction-based particle collector. This collector aims at submicron aerosol sampling in the supersonic free stream radially aside a sounding rocket body in the mesosphere (altitude of 85 km). The overall goal of the development process is to collect mesospheric aerosols for their physico-chemical analyses to gain further insights into high atmosphere processes: e.g. of aerosol particles from meteoric ablation and their potential impact on noctilucent cloud (NLC) formation. However, sampling of particles at these heights and their analyses is only possible by considerable costs and great effort by using sounding rockets, which is why only a sparse database is available so far. The development process and efficiency analyses are based on numerical simulations achieved by the software COMSOL Multiphysics®, where the simulation workflow is divided into two independent studies: First, with the CAD Import Module, the detailed rocket geometry (as far as relevant for the particle collection efficiency) is implemented into the model. Then, the supersonic flow field surrounding the rocket under varying flight attitudes is simulated by the High Mach Number Laminar Flow Interface by solving the Navier-Stokes equations for compressible fluids, whereby a steady state solution is obtained. Of particular interest for the design and arrangement of the probe collector is (a) the evaluation of the evolving flow field around the sounding rocket at the free stream Mach number of Ma = 1.75 (at 85 km height) and (b) the localization as well as the impact of the occurring shockwave on the particle sampling. Furthermore, the thickness of the boundary layer around the rocket body is investigated to ensure a particle sampling well away of perturbing influences. Additionally, for modeling the particle trajectories and thus the aerosol impactions on the probe collector, Particle Tracing for Fluid Flow is utilized, where Newtons second law is applied. For this purpose, a preliminary investigation of possible particle forces and their magnitude is performed and corresponding forces (drag and Brownian force) are considered in the model. With the final collector design, the number of impacted particles on collector surfaces are analyzed in a parameter study for aerosol sizes of 1.2 nm diameter at various number concentrations. Therefrom, the potential sampling efficiency of the probe collector is estimated. In conclusion, impactions onto designated collector surfaces are highly probable according to simulation results. Moreover, our COMSOL® model can be validated by measurement results of the future planned rocket flight.

Beware of phishing emails

Contact: algoritm@math.sk

Contact: algoritm@math.sk

Beware of phishing emails

Contact: algoritm@math.sk

Contact: algoritm@math.sk

An H(div)-Conforming E-HDG Method for the Incompressible Resistive MHD equations

Algebraic stabilizations of convection-diffusion problems and their convergence on general meshes

Oscillation-free numerical scheme for the Biot's model

Computational Multiscale Modelling of Glioblastoma Growth and Spread within Fibrous Brain Environment

Modeling root water uptake activity in the unsaturated water flow framework

A Macroscopic Model for Unsaturated Flow in Deformable Evolving Porous Media

Robust time-discretization, linearization and adaptive algorithms for coupled problems in porous media

A multi-scale model for freeze/thaw-induced pressure generation in maple trees

An iterative scheme for the stochastic Stefan problem

Image segmentation and its application to track a flame/smoldering front in combustion

Fixed-stress method for a class of nonlinear poroelasticity problems

Maximal monotone operator technique for solving Hamilton-Jacobi-Bellman equations arising in optimal portfolio selection problem

A new algorithm for surface reconstruction using a semi-Lagrangian scheme with local interpolator

Some numerical models for multi-material interaction in compressible or incompressible regimes

Evolutionary PDEs with Volterra operators: direct and inverse source problems

Dissipation-based WENO stabilization for high-order finite element discretizations of hyperbolic problems

Approximations of linear elliptic problems with irregular data on general simplicial grids

Limiter-based entropy stabilization of semi-discrete and fully discrete schemes for nonlinear hyperbolic problems

Parental bonus in pension systems

Mathematical modeling of freezing inception in a porous medium

Pharmacological models and numerical algorithms for the refinement of therapeutic approaches for retinal diseases

Oscillations in diffusion-driven gene regulatory networks for nuclear receptors

A quadrature-free p-adaptive discontinuous Galerkin discretization for the shallow water equations

Enforcing cell entropy inequalities using subcell limiting

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A Comparison Study of ADI and ADE Methods of the Black-Scholes equation on option pricing Models

Numerical Simulation of Water Freezing in a 3D Container Filled with Glass Beads

On the estimation of blood hemolysis index from viscoelastic stretch model

Model Reduction and Learning for PDE Constrained Optimization

Learning the solution operator of Hamilton Jacobi Bellman equations using physics-informed DeepONets

Path-based data envelopment analysis models with direction defined using the anti-ideal point

A fast numerical method for the operator solution of the generalized Rosen-Zener model

First and second order optimisation for solving initial value problems with neural forms on subdomains

Image Segmentation with Shape Compactness Regularization

Second order bounds in time for POD-ROM methods for the Navier-Stokes equations

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An improved Frankot and Chellappa method for surface normal integration using fuzzy concepts

Energy-preserving numerical methods for some dispersive shallow water models

Applications of constrained forced curvature flow

Direct Parallel-in-Time method based on Spectral Deferred Correction

Solving the fixed gravimetric boundary value problem using mapped infinite elements

Obstacle detection in Stokes fluid flow using a novel shape optimization approach

Bilevel Optimization with a No-Reference Image Statistics Based Score-Predictor Loss

Algebraic error in Adaptive Finite Element Method

Electric Field Predictions Using Physics-Informed Neural Networks

Model order reduction techniques for reactive transport problems

ALE based MOR for transport dominated problems: calibration, optimization and regression

Monolithic Convex Limiting for Legendre–Gauss–Lobatto Discontinuous Galerkin Spectral Element Methods

Localized numerical stabilization based on conformation tensor spectrum for viscoelastic fluids flows simulations

Recent advances in well-balanced methods for systems of conservation laws

A Novel Approach to Flux Balance Analysis in Genome-Scale Metabolic Modeling Using Dual Form Anderson Acceleration with Loopless Constraints

Steklov properties of the Helmholtz operator in the plane

The role of volatility in guaranteed bond funds

Predicting the persistence or extinction of species using integro-differential equations

Convergence of the finite element method on extremely deformed meshes

An experimental analysis of the K-SVD algorithm

3D high-resolution numerical modelling of altimetry-derived marine gravity data using FVM

Sketching and Recycling GMRES for a Sequence of PDE Solves

Adaptively optimised transmission conditions in Schwarz methods

Augmented Lagrangian Acceleration of Global-In-Time Oseen Solvers

PhysicsML: Harnessing the Power of AI in Technology Development

AI-Driven Fluid Dynamics

Piece-wise Symplectic Model Reduction on Quadratically Embedded Manifolds

Guaranteed and robust L2-norm a posteriori error estimates for 1D linear advection(-reaction) problems

Decomposition Methods for Training Neural Networks

Computational smeared damage in the macroscopic analysis of quasi-brittle materials and structures

Active learning of Gaussian Process Regression surrogates from simulated training data

Learning local Dirichlet-to-Neumann maps of nonlinear elliptic PDEs with rough data

Towards Operator Learning for Ionic Models in Biomathematics

Inferring passive realizations from frequency data via spectral factorization

Parallel in time algorithms for control problems

Nonlinear preconditioning for training of physics-informed neural networks

Towards instance-dependent approximation guarantees for scientific machine learning using Lipschitz neural networks