bluuebunny/crossref_metadata_2025_split huggingface dataset:
On determining the vortex core center in wing wake at M = 2
Authors: Shevchenko A M , Shmakov A S , Kulikov V V 
Published: December 2019

Abstract
The paper presents the processing of the results of numerical simulation of the vortex flow in the wing wake, the purpose of which is to search for the vortex core center. It is based on the results of numerical simulation of the vortex flow in the wake behind of the rectangular wing, performed at the Keldysh Institute of Applied Mathematics RAS. The center of the vortex core was determined in several ways: by the minima of the total and static pressure, the axial Mach number, mass flow rate, the maximum of axial vorticity, and as the center of mass of the axial vorticity distribution. A comparison of the results of determining the position of the vortex core center showed good quantitative agreement. As a result dependencies of vortex core center coordinates on longitudinal coordinate were obtained.
Experimental research of the supersonic core length in the supersonic jet flowing from the rectangular micro-nozzles with different aspect ratios
Authors: Timofeev I V , Aniskin V M 
Published: December 2019

Abstract
The supersonic core length of the air microjets flowing from rectangular micro-nozzles with different aspect ratios has been experimentally studied. The height and width of the nozzles varied from 119 to 135 μm and from 927 to 2185 μm, respectively.
“N-wave” propagation in supersonic flow at flow past the flat plate with sharp edge
Authors: Yermolaev Yu G , Chudinova Yu I , Kosinov A D , Semionov N V 
Published: December 2019

Abstract
The paper discusses the results of an experimental study of the propagation of the “N-wave” in a supersonic flow and its interaction with the bow shock wave, which is formed at flowing around a flat plate with a sharp leading edge. It was found that the “N-wave” does not change its direction when interacting with the bow shock. However, this interaction leads to a reduction of the “N-wave”. Estimates of the propagation angles of the “N-wave” in a supersonic flow are also obtained.
Simulation of linearly extended streamer with planar geometry at atmospheric pressure
Authors: Alexandrov A L , Schweigert I V , Zakrevsky Dm E 
Published: December 2019

Abstract
The cold atmospheric plasma (CAP) jet is used in different applications, for example, in medicine. Typical plasma devices have the cylindrical symmetry. In this work, the new type of device with planar geometry of CAP jet is considered. The initiation of two-dimensional streamer and its propagation from linearly extended electrode to the treated surface is considered with the help of 2D fluid discharge model. Differently to the case of an axially symmetric plasma jet, the streamer head has a plate shape and the ionization wave propagates with considerably larger velocity.
Starting flow in an impulse wind tunnel with a throttled prechamber
Authors: Gounko Yu P , Kavun I N 
Published: December 2019

Abstract
The unsteady axisymmetric flow forming in the process of starting an impulse wind tunnel equipped with a throttled prechamber was numerically simulated. A regime with the operating flow Mach number M = 8 was under consideration. Numerical simulation on the basis of Reynolds-averaged Navier–Stokes code and the k-ω SST turbulence model was performed. The starting process was simulated as a sudden rupture of a diaphragm separating the prechamber volume with high pressure and temperature from low pressure part of the facility including a nozzle, an operating section and an exhaust vacuum tank.. The diaphragm rupture initiates a gasdynamic process associated with the Riemann problem when the primary shock wave arises which moves through the nozzle to the operating section. Computed data show another “inverse” shock wave emerging in the nozzle. A starting “shock-wave package” forms between these shock waves, it includes a flow portion of high temperature and pressure. The specificity is discussed of identified the characteristics and flow patterns forming during the process of moving the shock-wave package.
Direct Monte Carlo simulation of development of the Richtmyer-Meshkov instability on the Ar/He interface
Authors: Kashkovsky A V , Kudryavtsev A N , Shershnev A A 
Published: December 2019

Abstract
The Richtmyer-Meshkov instability developing on the interface between helium and argon gases hit by a propagating shock wave is simulated numerically. In contrast with conventional approach based on the Navier-Stokes equations, the simulation in the current paper is performed on the molecular level using the Direct Simulation Monte Carlo method. The data averaging over short time periods is employed to decrease statistical scattering. The instability development is successfully reproduced with relatively moderate computer resources used. The time evolution of the transmitted shock wave and contact surface velocities are retrieved from numerical data as well as the instability growth rates.
Modeling flows of underexpanded jets in a slot space
Authors: Kiselev S P , Kiselev V P , Zaikovskii V N 
Published: December 2019

Abstract
In the present paper, we report on the results of a study of supersonic gas flows in a slot space. It is shown that the structure of the ejected jet exhausting into a slot ambient space substantially depends on the friction force. The latter force leads to a substantial change of the supersonic jet, which acquires, instead of a barrel-shaped, a fan-shaped form. The results of numerical simulation are consistent with experimental data.
Numerical simulation of sonic boom near-field flow over 69-degree delta wing body
Authors: Kiseleva T , Lukeshevich S 
Published: December 2019

Abstract
Fast and accurate prediction of sonic boom intensity is important in performing design and optimization studies of a supersonic aircraft. The paper presents the computational mesh generation technique for sonic boom prediction in the near field of complex geometry body. Studies are done on a 69-degree delta wing body model used for testing various prediction techniques in the framework of the AIAA Sonic Boom Prediction Workshops.
Linear stability of supersonic boundary layer over a cooled porous surface
Authors: Kudryavtsev Alexey , Khotyanovsky Dmitry 
Published: December 2019

Abstract
The linear stability of the boundary layer at high supersonic Mach numbers on a flat plate with a cooled porous surface is studied. As is well known, at high supersonic speeds, both vortex disturbances of the first mode and acoustic disturbances of the second mode are unstable. The more unstable disturbances of the second mode can be stabilized using sound-absorbing porous coatings. At the same time, such coatings have a destabilizing effect on the disturbances of the first mode. Surface cooling is one of the factors potentially capable of preventing such a destabilization. Based on this assumption, in the present work, the linear theory of stability is used to consider the combined effect of a sound-absorbing coating and surface cooling.
The influence of nozzle geometry on the gas-dynamic structure of the supersonic nonisobaric jet
Authors: Kundasev S G , Zapryagaev V I , Kiselev N P , Rybak S P 
Published: December 2019

Abstract
The paper presents the investigation results of the flow structure of cold supersonic jets flowing out of model nozzles with a Mach number on the exit Ma
= 3.5: an axisymmetric nozzle, a nozzle with a rectangular critical section, a beveled nozzle with a rectangular critical section. Flow schlieren images and transverse measured total pressure profiles in the flow are presented. The influence of the critical section shape and the beveled exit section on the shock-wave structure of the flow is described.
Essay of thermodynamic description and optimization of Ranque effect
Authors: Latypov A F 
Published: December 2019

Abstract
This paper presents a thermodynamic description of Ranque effect. Including expansion and compression works into energy exchange provides a rational explanation of the observed effect. These works are performed by small portions of gas in polytropic processes. Rotational motion of the gas and presence of non-reversibility in the processes of expansion and compression are responsible for energy separation. A mathematical model with the use of the conservation laws and the polytropic expansion process was created. Optimization calculations for various values of the polytropic efficiency coefficient and the Mach number of hot gas outflow were performed. It has been obtained that the optimal relative values of exit-section area and the Mach number of inflowing high-pressure gas are invariant with respect to the values of the parameters mentioned above. Using this result, a practical model for optimizing operation process was elaborated. The efficiency coefficient of expansion work is determined during the optimization process. Using this result a practical technique of operational process has been developed.
Numerical simulation of a two-component gas flow near a highway
Authors: Lavruk and S A , Valger S A 
Published: December 2019

Abstract
Numerical simulation of the air flow near a highway was carried out taking into account injection of ethane through a system of low sources. Numerical model is based on full physical and mathematical models of continuum media and takes into account the phenomena of turbulent mixing of gas components in the surface boundary layer. Based on the calculation results, the fields of velocity distribution, turbulent parameters and impurity concentrations in characteristic sections near the road are obtained.
Numerical solution of the Vlasov-Poisson equations using a semi-Lagrangian WENO scheme implemented on GPU
Authors: Malkov E A , Poleshkin S O , Shershnev A A , Kudryavtsev A N 
Published: December 2019

Abstract
A numerical method for solving the Vlasov–Poisson equations using a high-order semi-Lagrange conservative WENO scheme is developed. The Vlasov–Poisson equations govern evolution of the collisionless self-interacting medium and are widely used in plasma physics and astrophysics, in particular for modeling dynamics of galactic systems. The method is implemented for computations on Graphical Processing Units (GPUs). The GPU code is validated using an exact unsteady analytical solution describing nonlinear oscillations of a plane self-gravitating layer. The comparison with numerical results obtained with the serial CPU code show a significant, up to 50 times, speed-up of the computations.
Study of the flow structure in boundary layer bleed channel at the hypersonic speed of external flow
Authors: Obodovskaia E A , Korotaeva TA , Goldfeld M A 
Published: December 2019

Abstract
The paper presents the study of the flow structure in a boundary layer bleed channel and calculation of the mass flow rate under the conditions of thick boundary layer incoming. The flow at Mach numbers of M = 3, 4, 6 and angle of attack 6° has been considered. In the framework of the problem, the Reynolds-averaged Navier-Stokes equations added with the k–ω SST turbulence model have been solved. Numerical simulation of the flow in the channel has been carried out using the Roe implicit scheme of the second order of accuracy. Pressure and temperature profiles at the outlet boundary obtained at the simulation of the flow around the inlet forebody have been used to specify the inlet boundary conditions for simulation of the flow through the boundary layer bleed hole. The pressure distribution obtained at numerical simulation of a flow in the boundary layer bleed channel has shown that there is a large high-pressure area caused by the presence of so-called “barrier shock” near the channel back wall. Thus here is a supercritical pressure drop which ensures a sonic flow in the bleed hole. This conclusion has been confirmed by the experimental data obtained for small supersonic speeds. Calculation of the mass-flow rate through exit cross-section of the cylindrical bleed channel has shown that the mass flow rate coefficient decreases 2.5 – 3 times with the Mach number increasing from 3 to 6. The mass flow coefficient also decreases by about 10% due to the change of conditions in the 3D flow before the bleed hole with the moving off from the symmetry plane.
Comparison of modern implementations of the direct simulation Monte Carlo method
Authors: Shugalevskaia N V , Shevyrin A A , Bondar Ye A 
Published: December 2019

Abstract
In this work, collisional schemes of the direct simulation Monte Carlo (DSMC) method are compared. The sensitivity of the schemes to the number of simulated particles is investigated. The original No-Time-Counter (NTC) scheme, proposed by G.A. Bird, its modification NTC-2007 and majorant collision frequency (MCF) scheme, proposed by M. S. Ivanov and S.V. Rogasinsky are considered. For the high-speed Couette flow with parameters corresponding to a near-continuum regime (speed ratio S is equal to 10, Knudsen number Kn is equal to 0.01) the convergence of shear stress component is analysed. Calculations with different total number of the simulated particles (in the range from 500 to 106) were performed. It was shown, that the deviation of NTC-2007 scheme from the reference solution is about four times larger as compared to the MCF scheme. The original NTC scheme exhibits much higher sensitivity to the number of simulated particles.
Simulation of the transition to turbulence in the boundary layer on complex-shaped bodies at an angle of attack
Authors: Sidorenko A A , Boiko A V , Demyanko K V , Kirilovskiy S V , Nechepurenko Yu M , Poplavskaya T V 
Published: December 2019

Abstract
The paper deals with the numerical simulation of the laminar-turbulent transition as the gas flow moves at a nacelle at transonic speeds. The laminar-turbulent transition position in the 3D boundary layer of the nacelle is found with the aid of the laminar-turbulent transition module based on the e
N
-method which involves the data of the numerical simulation of the laminar flow at the model with the gas-dynamic software package ANSYS Fluent. Performance of this module is demonstrated as the laminar-turbulent transition, caused by the Tollmien-Schlichting wave and crossflow instabilities, takes place. It is shown that the Tollmien-Schlichting wave instability is the dominating mechanism of the laminar-turbulent transition on the nacelle up to the angle of attack of 7°.
Historical precipitation data in Sumatra and Kalimantan from 1879 to 1900, by using Dutch colonial materials
Authors: Kajita R 
Published: December 2019

Abstract
Indonesia suffers from serious fire and haze problems occurring in the peatland areas of Sumatra and Kalimantan. Haze has become an international issue in Southeast Asia, and Indonesia must now implement better prevention management for this severe crisis. To understand the meteorological conditions in Indonesia, it is important to analyze the historical precipitation ranging back to the colonial days. This study focuses on historical precipitation data observed during the Dutch colonial era. The observation records from 1879-1900 were recorded in historical materials called “Regenwaarnemingen in Nederlandsch-Indie”. The records not only include Batavia, but also other observation stations in Indonesia. In this study, the historical precipitation data in Sumatra (Medan, Jambi, Bengkalis) and Kalimantan (Pontianak, Banjarmasin, Amuntai) were reconstructed. By using these reconstructed precipitation data, I analyzed the annual precipitation fluctuation and mean monthly precipitation at six stations. The colonial materials have not yet been examined enough in the meteorological research field, and their historical data contribute to Indonesia’s historical research and climatic problems.
Mitigating simultaneous returning home after large-scale earthquakes: changing tourists’ intentions to stay through public support
Authors: Sakai K , Toyoda Y , Kanegae H 
Published: December 2019

AbstractThe difficulty in returning home in response to an earthquake is a serious problem for tourists, and it is necessary to understand the obstacles involved. The purpose of this study is to highlight factors that affect tourists’ intentions to return home or stay at the site during an earthquake disaster. Questionnaires were administered to tourists in Himeji Castle, and 467 valid responses were obtained. This study analyzed data by decision tree analysis using the tourists’ personal attributes, sightseeing style, and the degree of public support as independent variables and tourists’ behavioral intention as the dependent variable. In the situations related to public support, it became clear that proximity to one’s residential area and available transportation to Himeji had an influence. Further, it was found that public support strongly affected the behavioral intentions of tourists who came from afar. The results confirm that public support, tourists’ attributes, and sightseeing style affect intentions.
Low energy measures for residential buildings in tropical regime
Authors: Utama N A , Hendriana D , Irawan R , Hadi M , Bahtiar T A , Suhedi F 
Published: December 2019

Abstract
Towards the direction of developing sustainable building in tropical regime in general and in Indonesia in particular, facing multiple dilemmas, one of the dilemmas starting from the issue of the core variables in the green building which is low-energy buildings. By definition the main target for low energy building is the target for self-sustaining its energy supply while improving its efficiency. The issue of low energy building, in recent years, gained attention and moved towards a large-scale introduction in the residential sector. During this process, international criteria for energy use in buildings have become stricter, whilst the national standard for low energy building have not move forward only Jakarta municipality and Bandung municipality have developed its strategic regulation to achieve those targets. With a primary focus on landed house both for semidetached and detached houses, this study analyses how the measures the low-energy buildings which may further developed to reduce the energy use in the residential sector. The main attention is on the designing the façade, wind flow and local material performances. A thermal and fluid dynamics approach is applied, which here means that the concept of low-energy buildings is investigated from two main perspectives, namely thermal comfort with low energy uses by means of optimization for natural cooling. The thesis thus encompasses methods from both engineering approaches the studied areas through design, assessments and simulations. The thesis reveals how an increased process integration of the building’s energy system can improve the thermal comfort in low-energy buildings. Moreover, local climate data was use, local material was collected – to study how the heat influences can be predicted in a low-energy building in the Bandung climate. The thesis further focuses on the low-energy building as an element in our society.
The implementation of sustainable community-based environmental sanitation development policy (SLBM) in Tebo Regency
Authors: Hidayat B , Ophiyandri T , Tudi A 
Published: December 2019

Abstract
As it is a very necessary in daily life, the problems of sanitation are categorized as very basic problems in health sector. However, the pollution process cause of sanitation takes very long time; therefore, many people tend to ignore the dangerous posed to their health. Geographically, the residents in Tebo Regency are mostly located onthe riverbank, with inadequate sanitation facilities. Some of these sanitation facilities were built through the SLBM program, but they do not work optimally. This research was conducted to determine the factors of un-optimal SLBM program and to manage the future strategies for better SLBM. This study used a qualitative descriptive approach. The data were collectedusing survey methods, questionnaires, and interviews communities and local governments. The results showed that the implementation of the SLBM Sustainable Development Policy in TeboRegency was not optimal yet, due to several factors, including: lack of training / guidance, non-functioning CBOs, lack of trigger for healthy lifestyle, lack of socialization, lack of supporting facilities, inconsistent standards, lack of synergy between stakeholders, and lack of human resources. To improve sanitation access through the SLBM program, it requires commitment among stakeholders, support local governments to equip CBOs with training, Improve Socialization, and invite communities in the SLBM program.
A Study of Mechanical Performance of Supplementary Cementitious Material using Hot Water Curing
Authors: Hamzah S , Aprianti E 
Published: December 2019

Abstract
This study aims to investigate mechanical properties of supplementary cementitious material (SCM) using different curing condition. The utilization of huge number of agricultural waste material due to amount type has been disposed-off and being hazardous to the environment. This problem lies into reuse and renew those wastes to be useful materials. The combination of industrial and agricultural waste materials were used up to 50% in order to replace the use of cement. The result showed that using different curing step could be an effective way to produce high mechanical performance of mortars using supplementary cementitious materials.
Environmental health risk analysis due to PM10 during 2015’s smoke haze pollution in Sawahlunto City
Authors: Goembira F , Amin M , Ihsan T , Djafri D 
Published: December 2019

Abstract
This research was aimed to analyzed metal concentrations in particulate matter 10 (PM10) sampled from ambient air in Sawahlunto City during the occurrence of smoke-haze pollution in 2015. The metal contents comprise of Al, Cr, Mn, Co, Ni, and Cd, which represented the potential for both non-carcinogenic and carcinogenic illnesses. The obtained metal concentrations were further used to estimate health risk on human by using environmental health risk assessment approach. PM10 samplings were done by using Minivol Air Sampler while the metal concentration analysis was conducted by atomic absorption spectrophotometer after PM10 filter destruction. It was found out that during the smoke-haze pollution the PM10 concentrations were above Indonesian air quality standard and considered at hazardous level in accordance to the Indonesian air quality index. The results of environmental health risk assessment for children and adults show the Hazard Quotient (HQ) value > 1 for non-carcinogenic metals (Al, Cr, Mn). As for the carcinogenic metals (Co, Ni, Cd), it was estimated that the Excess Lifetime Cancer Risk (ELCR) > 10-6 for both children and adults. It can be concluded that the occurrence of smoke-haze pollution in Sawahlunto City in 2015 increased the risk of cancer illnesses in both children and adults due to the high metal concentrations in PM10.