Tunable interactions in colloids, induced by rotating electric or magnetic fields, provide a flexible and promising tool for self-assembly of soft materials, as well as for fundamental particle-resolved studies of phase transitions and other generic phenomena in condensed matter. In the case of two-dimensional systems and the in-plane rotating fields, the interactions are known to have a long-range (dipolar) attraction and an expressed three-body part at short distances, but still remain poorly understood. Here, we show that the interactions and polarization mechanisms governing the tunable interactions can be described, calculated, and analyzed in detail with the diagrammatic method we proposed. The diagrams yield a clear illustration of different polarization processes contributing to the Keesom, Debye, London, self, and external energies, classified in colloids similarly to intermolecular interactions. The real tunable interactions, obtained with the boundary element method, can be simply and accurately interpolated with the set of basis of the diagrams attributed to different physically clear polarization processes. Calculation of large-distance behavior and interpolation of the many-body interactions (and analysis of the leading mechanisms contributing to them) excellently illustrate that the diagrammatic method provides deep insights into the nature of tunable interactions. The method can be generalized for multicomponent systems, suspensions of particles with a composite structure and a complicated shape. The results provide significant advance in theoretical methods for detailed analysis of tunable interactions in colloids and, therefore, the method is of broad interest in condensed matter, chemical physics, physical chemistry, materials science, and soft matter.

The paper is devoted to the comparative analysis of different CFD techniques used to solve the problem of high-pressure hydrogen release into the air. Three variations of a contemporary low-dissipation numerical technique (CABARET) are compared with each other and a conventional first-order numerical scheme. It is shown that low dissipation of the numerical scheme defines better resolution of the contact surface between released hydrogen and ambient air. As a result, the spatial structures of the jet and the reaction wave that arise during self-ignition are better resolved, which is useful for predicting the local effects of high-pressure hydrogen release. At the same time, the dissipation has little effect on the induction delay, so critical conditions of self-ignition can be reliably reproduced even via conventional numerical schemes. The test problem setups formulated in the paper can be used as benchmarks for compressible CFD solvers.

This paper is devoted to the analysis of the effect of gas injection on the efficiency of gaseous fuel burning. A coaxial burner with a perforated inner wall is presented in which the methane–air acceleration is observed. With the use of numerical analysis, it is demonstrated that the flame acceleration is related to the flow separation from the inner wall that, in turn, leads to the reduction in heat losses to the wall as well as to vortex formation and reduction in momentum losses. On the basis of the obtained results, a new technology of efficient burning of gaseous fuels can be proposed with the use of gas and/or liquid fuel injection.