▪ Abstract Recent considerable progress in the field of rarefied hypersonic computational fluid dynamics (CFD) gives reason to address its evolution to an independent CFD branch that covers many fundamental and closely related applied problems of high-altitude aerothermodynamics of space vehicles. The primary purpose of this review is to describe the main numerical methods and real gas models for investigation of problems of rarefied hypersonic flows, and to review results that we believe demonstrate most clearly the achievements and capabilities of the field of rarefied hypersonic CFD in the last years.

Computational hypersonic rarefied flows

Im diesem Dokument werden Aspekte der formalen zeitlichen Planung bzw. des Scheduling fur Bauprojekte anhand ausgewahlter Literatur diskutiert. Auf allgemeine Aspekte des Scheduling soll dabei nicht eingegangen werden. Hierzu seien als Standard-Referenzen nur Brucker (2004) und Pinedo (1995) genannt. Zu allgemeinen Fragen des Projekt-Managements sei auf Kerzner (2003) verwiesen. Im Abschnitt 1 werden einige Anforderungen und Besonderheiten der Planung von Baustellen diskutiert. Diese treten allerdings auch in zahlreichen anderen Bereichen der Produktionsplanung und des Projektmanagements auf. In Abschnitt 2 werden dann Aspekte zur Formalisierung von Scheduling-Problemen in der Bauwirtschaft diskutiert, insbesondere Ziele und zu berucksichtigende Restriktionen. Auf eine mathematische Formalisierung wird dabei allerdings verzichtet. Abschnitt 3 bietet eine Ubersicht uber Verfahren und grundlegende Techniken fur die Berechnung von Schedules. In Abschnitt 4 wird ein Uberblick uber vorhandene Software, zum einen verbreitete Internationale Software, zum anderen deutschsprachige Branchenlosungen, gegeben. Anschliesend werden Schlussfolgerungen gezogen und es erfolgt eine Auflistung der Literaturquellen.

https://kluedo.ub.uni-kl.de/files/1645/bericht74.pdf

Eine Übersicht zum Scheduling von Baustellen

The paper provides an overview of the use of coherent anti-Stokes Raman scattering (CARS) and spontaneous Raman scattering for diagnostics of low-temperature nonequilibrium plasmas and nonequilibrium high-enthalpy flows. A brief review of the theoretical background of CARS, four-wave mixing and Raman scattering, as well as a discussion of experimental techniques and data reduction, are included. The experimental results reviewed include measurements of vibrational level populations, rotational/translational temperature, electric fields in a quasi-steady-state and transient molecular plasmas and afterglow, in nonequilibrium expansion flows, and behind strong shock waves. Insight into the kinetics of vibrational energy transfer, energy thermalization mechanisms and dynamics of the pulse discharge development, provided by these experiments, is discussed. Availability of short pulse duration, high peak power lasers, as well as broadband dye lasers, makes possible the use of these diagnostics at relatively low pressures, potentially with a sub-nanosecond time resolution, as well as obtaining single laser shot, high signal-to-noise spectra at higher pressures. Possibilities for the development of single-shot 2D CARS imaging and spectroscopy, using picosecond and femtosecond lasers, as well as novel phase matching and detection techniques, are discussed.

https://iopscience.iop.org/article/10.1088/0022-3727/47/43/433001/pdf

Coherent anti-Stokes Raman scattering and spontaneous Raman scattering diagnostics of nonequilibrium plasmas and flows

The transition of planar shock waves over straight wedges in steady flows between regular and Mach reflection was numerically studied by the DSMC method for small Knudsen numbers. The hysteresis effect was observed at increasing and decreasing shock wave angle. Stability of regular and Mach reflection configurations to perturbations was examined and a possibility of transforming one configuration to the other by means of the perturbations was shown. The effect of starting conditions in the dual solution domain was clarified.

Statistical Simulation of the Transition between Regular and Mach Reflection in Steady Flows

A regularized Lagrangian finite point method for the simulation of incompressible viscous flows

We present the application of a meshfree method for simulations of interaction between fluids and flexible structures As a flexible structure we consider a sheet of paper In a two-dimensional framework this sheet can be modeled as curve by the dynamical Kirchhoff-Love theory The external forces taken into account are gravitation and the pressure difference between upper and lower surface of the sheet This pressure difference is computed using the Finite Pointset Method (FPM) for the incompressible Navier-Stokes equations FPM is a meshfree, Lagrangian particle method The dynamics of the sheet are computed by a finite difference method We show the suitability of the meshfree method for simulations of fluid-structure interaction in several applications

/pdf/a-meshfree-method-for-simulations-of-interactions-between-541znrjxv9.pdf

A Meshfree Method for Simulations of Interactions between Fluids and Flexible Structures

https://kluedo.ub.uni-kl.de/files/601/gruen_167.pdf

Adaptive Load Balance Techniques in Parallel Rarefied Gas Simulations

The study of space vehicle aerodynamics at the altitudes 80–120 km becomes more and more important. This is primarily caused by the development of new generation of space transportation systems, for which the mentioned altitudes are determining. This requires more comprehensive and detailed understanding of the problems of hypersonic aerodynamics at high flight altitudes.

Statistical Simulation of Highly Nonequilibrium Hypersonic Rarefied Flows

Rarefied numerical aerodynamic tools for reentry problems

The problems of the fire safety of oil and gas facilities are particularly relevant due to the increasing complexity of technological processes and production. Experimental studies of steel structures with three different types of plasters are presented to determine the time taken to reach the critical temperature and loss of bearing capacity (R) of the sample, as a result of reaching a rate of deformation growth of more than 10 mm/min and the appearance of the ultimate vertical deformation. The simulation of the heating of steel structures showed a good correlation with the results of the experiment. The consumption of the plaster composition for the steel column was predicted, which allowed a 38% reduction in the consumption of fireproofing. It was found that to obtain the required fire resistance limit, it is necessary to consider the fire regime and apply plaster compositions with a thickness of 30–35 mm, depending on their thermal characteristics. The dependence of thermal conductivity and temperature on density is obtained, showing that the use of plaster compositions with a density of 200 to 600 kg/m3 is optimal to ensure a higher fire resistance limit. It is shown that the values of thermal conductivity of plaster compositions at 1000 °C are higher by 8–10% if the structure is exposed to a hydrocarbon fire regime. It is shown that the values of the heat capacity of plaster compositions at 1000 °C are higher by 10–15% if the structure is exposed to a standard fire regime.

/pdf/thermal-characteristics-of-fireproof-plaster-compositions-in-gtsp9ym4.pdf

Sergey Antonov

Papers

A Meshfree Method for Simulations of Interactions between Fluids and Flexible Structures

Adaptive Load Balance Techniques in Parallel Rarefied Gas Simulations

Statistical Simulation of Highly Nonequilibrium Hypersonic Rarefied Flows

Rarefied numerical aerodynamic tools for reentry problems

Thermal Characteristics of Fireproof Plaster Compositions in Exposure to Various Regimes of Fire