Simulating anisotropic flows with isotropic lattice models via coordinate and velocity transformation

We propose a rectangular lattice Boltzmann model for anisotropic flows based on coordinate and velocity transformation. Unlike other existing rectangular models which tuned the lattice Boltzmann algorithm to fit the rectangular or cuboid lattice grids, here we apply the general lattice Boltzmann method to solve the transformed system over regular square lattice grids. The method is tested with simulations of representative anisotropic flows, including flows in narrow straight and wavy channels, the Taylor–Green vortex flow, and the flow through an elliptical particle array. These simulations show that in general our method produces satisfactory results; however, the aspect ratio [Formula: see text] is limited to relatively large values ([Formula: see text]). The effects of [Formula: see text] on simulation accuracy and stability have been carefully examined, and a possible remedy to improve these concerns has been proposed. The method and analysis could be useful for future development of more robust and practical anisotropic lattice Boltzmann models for realistic simulations.

Forensic Uncertainty Quantification for Experiments on the Explosively Driven Motion of Particles

Six explosive experiments were performed in October 2014 and February of 2015 at the Munitions Directorate of the Air Force Research Laboratory with the goal of providing validation-quality data for particle drag models in the extreme regime of detonation. Three repeated single particle experiments and three particle array experiments were conducted. The time-varying position of the particles was captured within the explosive products by X-ray imaging. The contact front and shock locations were captured by high-speed photography to provide information on the early time gas behavior. Since these experiments were performed in the past and could not be repeated, we faced an interesting challenge of quantifying and reducing uncertainty through a detailed investigation of the experimental setup and operating conditions. This paper presents the results from these unique experiments, which can serve as benchmark for future modeling, and also our effort to reduce uncertainty, which we dub forensic uncertainty quantification (FUQ).

SELF-CLEANING FILTER WITH THE USE OF MAGNETICALLY CONTROLLED PARTICLES

Представлена конструкция фильтра с динамичным фильтрующим слоем на основе магнитоуправляемых частиц. В качестве основного подхода к технической реализации конструкции фильтра использован метод управления структурой массива частиц внешним вращающимся магнитным полем. Показаны возможность создания динамичной пористой структуры фильтроэлемента с плотной упаковкой частиц, а также процесс самоочистки установки, не требующий дополнительных инженерных коммуникаций. Основные характеристики самоочищающегося фильтра показали хорошую сходимость данных теоретического расчета параметров фильтрации и эксперимента. Основными результатами работы являются: механизм формирования динамичной пористой структуры фильтроэлемента и его морфология, анализ качества фильтруемой среды после прохождения через фильтроэлемент, а также основные технические характеристики фильтра и его возможности. Полученные результаты – основа для проведения исследований разработанной установки самоочищающегося фильтра с динамичной пористой структурой с перспективой применения в процессах водоподготовки в промышленном масштабе. The design of the filter with a dynamic filter layer based on magnetically controlled particles is presented. As the main approach to the technical implementation of the filter design, the method of controlling the structure of the particle array by an external rotating magnetic field is used. The possibility of creation of a dynamic cellular structure of a close-packed filter element of particles and also process of self-wiping of the installation which is not demanding padding utilities is shown. Experimental and theoretical data of the main filtration equipment characteristics showed a good convergence. The main results of work are the mechanism of formation of a dynamic cellular structure of a filter element and its morphology, the analysis of quality of the filtered environment after passing through a filter element and also the main technical the characteristic of the filter and its opportunity. The received results are a basis for carrying out a number of researches on scaling of the developed installation of the self-cleaning filter with a dynamic cellular structure to the commercial scale with the prospect of application in water treatment processes.