Article
Mechanics
Junkai Huang, Xin Zhao, Hao Jiang
Summary: This study presents a numerical method for liquid jet atomization in supersonic gas crossflow, considering compressibility of the gas and incompressibility of the liquid. The simulation involves high-order accurate schemes for gas flows and the Chorin projection method for liquid flow. It also analyzes the breakup process and the effect of Mach number on liquid jet atomization.
Article
Physics, Fluids & Plasmas
V. A. Bityurin, A. N. Bocharov, A. S. Dobrovolskaya, N. A. Popov, A. A. Firsov
Summary: A physical and numerical model of a longitudinal-transverse discharge in a supersonic air flow is proposed in this study. The model not only considers the traditional mechanisms of interaction between the discharge and the flow, but also takes into account the processes of dissociation and ionization in strong reduced electric fields. The results show that, in a two-dimensional model of a direct current discharge, the current loop is carried away by the flow until a strong reduced electric field near the electrodes provides sufficient ionization to form an alternative current channel. The process of current reconnection is periodic and the lifetime of the current loop is proportional to the current amplitude.
PLASMA PHYSICS REPORTS
(2023)
Article
Energy & Fuels
Alexander Firsov, Valentin Bityurin, Dmitriy Tarasov, Anastasia Dobrovolskaya, Roman Troshkin, Aleksey Bocharov
Summary: This study focuses on the properties of DC discharge in supersonic airflow and its applicability in combustion simulations. Experimental research supplemented by numerical simulation was conducted to obtain two-dimensional distributions of temperature, current density, chemical composition, and other discharge and flow parameters. The production of a significant amount of atomic oxygen, which accelerates combustion, was observed.
Article
Engineering, Multidisciplinary
Yaxin Zhen, Tong Gu, Ye Tang
Summary: This paper analyzes the aeroelastic characteristic and active control of one-dimensional acoustic black hole structures in supersonic airflow. The motion equation of the structures with attached piezoelectric elements is established using Hamilton's principle. The first-order piston theory is used to simulate the aerodynamic pressure, and a controller is designed based on speed feedback and proportional feedback algorithms. Numerical simulations are conducted to study the variation of natural frequency with aerodynamic pressure and analyze the influences of piezoelectric actuators and sensors on aeroelastic flutters.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Physics, Fluids & Plasmas
E. E. Perevoshchikov, A. A. Firsov
Summary: This study focuses on the stable operation and parameters of a longitudinal-transverse discharge in a supersonic flow. High-speed imaging and data acquisition were used to analyze the variation of discharge length, current, and voltage over time. The main objective was to understand the dynamics of the DC discharge and establish relationships between its geometrical and electrical parameters. The experiments aimed to gather detailed data on the influence of interelectrode distance and discharge current on discharge length, voltage, power release, and determine typical breakdown frequencies based on discharge parameters. The electrode fall voltage was also determined.
PLASMA PHYSICS REPORTS
(2023)
Article
Mechanics
Chenguang Lai, Liangkui Tan, Shigeru Obayashi
Summary: This study investigates the aeroacoustic control mechanism of a plasma jet on a high-speed moving wing under a wing-in-ground effect. The results show that different plasma excitation modes interfere with the vortex generation and development in different ways to achieve aeroacoustic reduction. The modal analysis reveals that the change in each order of the modal corresponds to the energy decrease at the peak frequency and the energy increase at high frequencies.
Article
Engineering, Aerospace
Rio Baidya, Sven Scharnowski, Charitha M. de Silva, Manuj Awasthi, Christian J. Kaehler
Summary: The near wake of a circular cylinder in a high-Reynolds-number regime was investigated using particle image velocimetry. The study found that the mean wake features for subsonic and supersonic cases are very different, and the variation in observed wake width is due to the differing paths of eddies.
Article
Mechanics
Ming Yu, Chunxiao Xu
Summary: In this study, predictive models for near-wall velocity and temperature fluctuations in compressible wall-bounded turbulence are developed based on the model proposed by Marusic et al. The models incorporate the effects of large-scale motions in the outer region on near-wall turbulence and are validated through direct numerical simulations. The results show good agreement between the predicted fluctuations and the actual results.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Rui Zhong, Qingshan Wang, Shuangwei Hu, Bin Qin, Cijun Shuai
Summary: The study aims to develop a general meshless vibration model for analyzing the modal properties and stochastic responses of laminated rectangular and sectorial plates in aero-thermal environments. The model combines the supersonic piston theory with the thermo-elastic theory to consider the thermal and aerodynamic effects. The vibration behaviors under various boundary constraints are solved using Chebyshev meshless shape functions and the pseudo excitation method (PEM) is adopted for stochastic analysis. The accuracy and stability of the model are validated through convergence checks and verification studies.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Engineering, Environmental
J. Mikes, S. Pekarek, O. Hanus
Summary: This paper investigates the influence of airflow orientation on the microdischarges of the surface dielectric barrier discharge in cylindrical configuration. The study examines the effects of varying air input, the number of input nozzles, and the geometry of the active electrode on the flow regime and temperature field distribution in the discharge chamber. The findings reveal that the orientation of microdischarges with respect to the airflow is affected by the change of active electrode geometry.
OZONE-SCIENCE & ENGINEERING
(2023)
Article
Physics, Applied
Xiao Wang, Hui-Jie Yan, Yu-Ying Wang, Si-qi Yu, Ting Li, Jian Song
Summary: The surface charges in nanosecond pulsed dielectric barrier discharge under quiescent air and airflow were detected based on the Pockels effect of electro-optical crystals. In quiescent air, the surface charge spot propagates and moves in a certain direction due to the combination of the transverse electric field and thermal accumulation. The position of the surface charge spot remains fixed throughout a single discharge cycle (0.83 ms), and noticeable decay of surface charges occurs over time. When airflow is introduced, the propagation and movement of surface charges are accelerated, leading to changes in discharge mode and charge distribution.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Yongkai Chen, Carlo Scalo
Summary: Investigation on the effects of wall permeability on isothermal-wall supersonic channel flow turbulence was conducted using large-eddy simulations. Results showed that significant changes in near-wall turbulence structures occurred only when the wall impedance was set to 0.50, primarily due to contribution from instability waves triggered by permeability.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Engineering, Manufacturing
Moritz Mascher, Raphael Hess, Christian Hopmann, Thomas Bergs
Summary: To increase the flow path length in the mould for thin-walled packaging applications or thick-walled technical components with long flow paths, a mould surface machined by electrical discharge machining is used. The influence of the mould surface structure on the achievable flow path length is investigated by varying process parameters, moulding compound, and surface roughness. While there is a material dependent, positive influence of the surface roughness on the flow path length, it is small compared to other influences such as mould or melt temperature.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Mechanics
Qiong Liu, Yiyang Sun, Chi-An Yeh, Lawrence S. Ukeiley, Louis N. Cattafesta, Kunihiko Taira
Summary: Resolvent analysis is used to develop a control strategy to attenuate pressure fluctuations in turbulent flow over a rectangular cavity, achieving significant reduction in pressure fluctuations. Introducing three-dimensional unsteady blowing along the cavity leading edge effectively suppresses oscillations and reduces pressure root mean square level along cavity walls. The control strategy based on resolvent analysis shows promise for application at higher Reynolds numbers with further validation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Chemical
Lizhuo Zhu, Haifeng Lu, Xiaolei Guo, Haifeng Liu
Summary: The study shows that under the action of pulsed airflow with a smaller duty cycle, stable flow of jammed granular materials can be effectively triggered. Under proper conditions, hopper flow can transition from a classic arch-breaking mode to a liquid-like free-flowing mode. The flow rate of powder in the free-flowing mode decreases as the powder bed height decreases, overturning previous assumptions.
Article
Engineering, Aerospace
Alec Houpt, Sergey Leonov, Timothy Ombrello, Campbell Carter, Robert John Leiweke
Article
Physics, Applied
Tatsunori Hayashi, Alec W. Houpt, Sergey B. Leonov, Hirotaka Sakaue
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2019)
Article
Physics, Applied
A. A. Firsov, S. B. Leonov, M. A. Shurupov, D. A. Yarantsev
Article
Physics, Applied
Ivan Moralev, Pavel Kazanskii, Valentin Bityurin, Alexey Bocharov, Alexander Firsov, Eugenii Dolgov, Sergey Leonov
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2020)
Editorial Material
Physics, Applied
Sergey B. Leonov, Svetlana Starikovskaya, Timothy Ombrello, Mark A. Cappelli
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2020)
Article
Engineering, Aerospace
Philip A. Lax, Sergey B. Leonov
Article
Engineering, Aerospace
Alec Houpt, Sergey Leonov
Summary: A novel configuration of focused laser differential interferometry (CFLDI) using cylindrical lenses was developed for closer probing of flat-plate boundary layers. The system was tested in a supersonic wind tunnel and successfully filtered sidewall boundary layers while measuring density fluctuations. This serves as an initial validation of CFLDI maintaining spatial filtering similar to regular FLDI.
Article
Thermodynamics
Sergey B. Leonov, Skye Elliott, Campbell Carter, Alec Houpt, Philip Lax, Timothy Ombrello
Summary: This paper investigates the modes of plasma-stabilized supersonic combustion with a cavity-based flameholding configuration, testing different combustion scenarios and comparing rail discharge performance with Plasma-Injection Modules. Dimensionless analysis shows good agreement of in-cavity combustion mode with the Ozawa stability diagram, while plasma-assisted bulk combustion differs substantially from this formalism.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Thermodynamics
Skye Elliott, Mitsugu Hasegawa, Hirotaka Sakaue, Sergey Leonov
Summary: This work focuses on experimental characterization of shock-dominated flow structures controlled by a filamentary plasma array. The study investigates the interaction between shock waves and plasma, effects on the flowfield, and the mechanism of plasma on total pressure losses in the duct.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2022)
Article
Thermodynamics
Skye Elliott, Philip Lax, Sergey B. Leonov, Campbell Carter, Timothy Ombrello
Summary: This study investigates the mixing and flameholding characteristics of a plasma stabilized planewall supersonic combustor. Fuel injection, ignition, and flameholding are achieved using Plasma Injection Modules (PIMs). Experimental results show that PIM actuation increases jet penetration, crossflow expansion, and initiates fuel jet breakup, leading to an increase in jet cross sectional area by over 20% when plasma is added.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2022)
Article
Energy & Fuels
Philip Andrews, Philip Lax, Sergey Leonov
Summary: This study focuses on the control of shock wave positioning in shock-dominated flows. Experiments are conducted to investigate the triggering effect of patterned near-surface electrical discharges on shock wave reflection from plane walls. Detailed analysis of the plasma-shock wave interaction is done using Mie scattering, schlieren imaging, and wall pressure measurements.
Article
Physics, Fluids & Plasmas
Skye Elliott, Arthur Dogariu, Celia Coates, Sergey B. Leonov
Summary: This study examines the dynamics of volumetric electric charge generated by a single pin electrode streamer corona in atmospheric air. The residual charge from positive polarity pulses affects subsequent discharges, while negative polarity pulses partially neutralize the previous charge and generate a high-amplitude electric field region. The EFISH method and electrostatic probes were used to evaluate the electric field magnitude and polarity of corona discharges.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Philip Andrews, Philip Lax, Skye Elliott, Alexander Firsov, Sergey Leonov
Summary: This study introduces the supersonic wind tunnel facility SBR-50 at the University of Notre Dame, which is used for experimental research on shock wave interactions, supersonic combustion, and plasma-based flow control. The objective of the study is to characterize the flow dynamics and gas temperature in the facility. Two measuring methods, thermocouple measurements and schlieren-based thermal mark velocimetry, were used to collect experimental data, which were compared with 3D Navier-Stokes modeling. The study demonstrates that the original facility schematics allow for longer operation with a constant stagnation temperature compared to adiabatic cooling.
Review
Engineering, Aerospace
Philip A. Lax, Sergey B. Leonov
Summary: Various reduced-order nucleation rate models, both classical and non-classical, are compared to experimental values for CO2 homogeneous nucleation rate in supersonic nozzles. The most accurate models are utilized in simulations of condensing supersonic expansion flows, and experimental results for CO2 condensation onset points are compared to simulations and new data from the SBR-50 facility at the University of Notre Dame.
Article
Physics, Fluids & Plasmas
A. V. Efimov, A. A. Firsov, N. S. Kolosov, S. B. Leonov
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2020)
