ORIGINAL_ARTICLEThe tank sloshing problem is very important at design time in LNG/LPG ships. This problem causes impulsive loads to ship structures and is often treated as a non-linear one. In order to estimate these impulsive loads, properly many studies have been carried out through both experimental and numerical approaches. Impulsive pressure on the wall of a tank induced by forced multi-degree oscillations is focused in this research. It is shown in the past authors’ experiment that forced multi-degree oscillations cause stronger impulsive pressure as compared to individual oscillations. Numerical analysis by a particle method based on finite volume technique is introduced in this study to simulate the above phenomena. The suggested particle method is shown to be useful for simulating a strong nonlinear phenomenon. The authors discuss the calculated results of pressure time history with the experimental results.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_01.pdf2019-06-3071610.15240/tul/004/2019-1-001SloshingImpulsive load and pressureParticle methodFinite volume methodShigeyukiHibihibiteru@nda.ac.jp1National Defense Academy, Department of Mechanical Systems EngineeringAUTHORKazukiYabushitayabu@nda.ac.jp2National Defense Academy, Department of Mechanical Systems EngineeringAUTHORHIBI, S.: Study on the impulsive pressure of tank oscillating by force towards multiple degrees of freedom. EPJ Web of Conferences. 2018, Vol. 180, Paper No. 02034.110.1051/epjconf/201818002034YABUSHITA, K.; HIBI, S: to be posted. Journal of Marine Science and Technology2MONAGHAN, J. J.: Simulating Free Surface Flows with SPH. Journal of Computational Physics. 1994, Vol. 110, Issue 2, pp. 399–406.3

ORIGINAL_ARTICLEThe performance of the last stage of the LP part of a steam turbine is strongly influenced by the effectivity of the downstream exhaust casing. The 90° turning of the flow in a relatively short axial distance is a major cause of losses and the design of low-loss diffuser still remains a challenge for mechanical engineers. In this paper, results of studies on a several steam turbine exhaust diffuser designs of SKODA have been reported. Several experimental measurements were carried out in the special sector model air test rig. This unique test rig allows visual observation of the flow by the Schlieren method and evaluating the loss coefficient of static pressure in the diffuser. The test rig allows achieving very high (supersonic) speeds. The range of observed velocities was from 30 to 360 m/s. The experimental data from these measurements are very useful to be able to predict the exhaust casing losses during the real operation of steam turbine in non-designed states. The behaviour of individual diffuser designs has been discussed.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_02.pdf2019-06-30172710.15240/tul/004/2019-1-002DiffuserSteam turbineExhaust casingPressure lossRobertKalistarobert.kalista@doosan.com1Doosan Skoda Power, Experimental Research of FlowAUTHORLukášKanta2University of West Bohemia, Department of Power System EngineeringAUTHORLevFeldberg3NPO CKTI, Joint-Stock Company, Polzunov Scientific And Development Association on Research and Design of Power EquipmentAUTHORM. HOZNEDL et al.: The Pressure Field at the Output From a Low Pressure Exhaust Hood and Condenser Neck of the 1090 MW Steam Turbine: Experimental and Numerical Research. In: Proceedings of ASME Turbo Expo 2018. Oslo, Norway. 2018, Paper No. GT2018-75248. ISBN 978-0-7918-5117-3. 110.1115/GT2018-75248KALISTA, R.; MRÓZEK, L.; HOZNEDL, M.: The Experimental Investigation of the Internal Support Effects on Exhaust Casing Pressure Recovery. In: Proceedings of ASME 2017 International Mechanical Engineering Congress and Exposition. 2017, Paper No. IMECE2017-70279. ISBN 978-0-7918-5841-7. 210.1115/IMECE2017- 70279HOZNEDL, M.; PACÁK, A.; TAJČ, L.: Effect of internal elements of the steam turbine exhaust hood on losses. EPJ Web of Conferences. 2012, Vol. 25, Paper No. 01024.310.1051/epjconf/20122501024FU, Jing-Lun; LIU, Jian-Jun: Investigation of Influential Factors on the Aerodynamic Performance of a Steam Turbine Exhaust System. In: Proceedings of ASME Turbo Expo 2010. Glasgow, UK. 2010. Paper No. GT2010-22316. ISBN 978-0-7918-4402-1. eISBN 978-0-7918-3872-3.410.1115/GT2010-22316ФЕЛЬДБЕРГ, Л. А.: Аэродинамическое исследование диффузора цнд турбины Шкода на секторной модели. внутренний отчет для SKODA. Контракт 203/290912/11. 2009.5TAJČ, L. et al.: The experimental investigation of the influence of the flow swirl and the tip clearance on aerodynamics characteristics of exhaust hoods. In: Turbomachinery 2007. Athens, Greece. 2007, pp. 395–404.6ДОБКЕС, А. П.; НИШНЕВИЧ, В. А.; ФЕЛЬДБЕРГ, Л. А.; ЮШКЕВИЧ, Ю. Э.: Устройство для исследования газовых потоков оптическими методами. Авторское свидетельство СССР 811116.7

ORIGINAL_ARTICLEThe laboratory experiments for identification of mechanisms of the spume droplet’s formation in marine atmospheric boundary layer, when strong wind tears off water from the crest of the waves, were carried out at the High-speed wind-wave flume of IAP RAS. The main mechanism responsible for the generation of spume droplets is bag breakup fragmentation of small-scale disturbances that arise at the air–water interface under the strong wind. This work concentrates on investigation of a separate bag-breakup event that was forced to occur in a dried high-speed wind-wave flume. The details of the bag-breakup fragmentation were investigated qualitatively and quantitatively using synchronized multiperspective high-speed video recording in shadowgraph configuration.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_03.pdf2019-06-30283810.15240/tul/004/2019-1-003Wind-wave interactionAtmospheric boundary layerWind-wave flumeSea sprayBagbreakup High-speed videoParticle tracking velocimetryAlexanderKandaurovkandaurov@hydro.appl.sci-nnov.ru1Institute of Applied Physics RAS, Geophysical Research DivisionAUTHORDaniilSergeevsergeev4758@gmail.com2Institute of Applied Physics RAS, Geophysical Research DivisionAUTHORYuliyaTroitskayayuliya@hydro.appl.sci-nnov.ru3Institute of Applied Physics RAS, Geophysical Research DivisionAUTHORANDREAS, E. L.; EMANUEL, K. A.: Effects of Sea Spray on Tropical Cyclone Intensity. Journal of the Atmospheric Sciences. 2001, Vol. 58, pp. 3741–3751.110.1175/1520-0469(2001)058<3741:EOSSOT>2.0.CO;2ANDREAS, E. L.: Fallacies of the Enthalpy Transfer Coefficient over the Ocean in High Winds. Journal of the Atmospheric Sciences. 2011, Vol. 68, pp. 1435–1445.210.1175/2011JAS3714.1BAO, J.-W.; FAIRALL, C. W.; MICHELSON, S. A.; BIANCO, L.: Parameterizations of Sea-Spray Impact on the Air–Sea Momentum and Heat Fluxes. Monthly Weather Review. 2011, Vol. 139, pp. 3781–3797. 310.1175/MWR-D-11-00007.1SOLOVIEV, A. V.; LUKAS, R.; DONELAN, M. A.; HAUS, B. K.; GINIS, I.: The airsea interface and surface stress under tropical cyclones. Scientific Reports. 2014, Vol. 4, Article No. 5306.410.1038/srep05306TAKAGAKI, N. et al.: Strong correlation between the drag coefficient and the shape of the wind sea spectrum over a broad range of wind speeds. Geophysical Research Letters. 2012, Vol. 39, Issue 23.510.1029/2012GL053988TAKAGAKI, N.; KOMORI, S.; SUZUKI, N.; IWANO, K.; KUROSE, R.: Mechanism of drag coefficient saturation at strong wind speeds. Geophysical Research Letters. 2016, Vol. 43, Issue 18, pp. 9829–9835.610.1002/2016GL070666ANDREAS, E. L.: A review of spray generation function for the open ocean in Atmosphere. In: Perrie, W. (ed.), Ocean Interactions Volume 1. 2002, pp. 1–46.7TROITSKAYA, Y. et al.: Bag-breakup fragmentation as the dominant mechanism of sea-spray production in high winds. Scientific Reports. 2017, Vol. 7, Article No. 1614.810.1038/s41598-017-01673-9TROITSKAYA, Y. I. et al.: Laboratory and theoretical modeling of air-sea momentum transfer under severe wind conditions. Journal of Geophysical Research: Oceans. 2012, Vol. 117, Issue C11. 910.1029/2011JC007778NATIONAL METEOROLOGICAL LIBRARY in conjunction with the MET OFFICE’S NATIONAL CLIMATE INFORMATION CENTRE: National Meteorological Library and Archive Fact sheet 6 — The Beaufort Scale. [online]. 2010. Available from WWW: http://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/s/j/10_0425_factsheet _6_beaufort.pdf10SERGEEV, D. A.; KANDAUROV, A. A.; VDOVIN, M. I.; TROITSKAYA, Y. I.: Studying of the surface roughness properties by visualization methods within laboratory modeling of the atmospheric-ocean interaction, Sci Vis. 2015, Vol. 7, Issue 5, p. 109.11KANDAUROV, A. A.; TROITSKAYA, Y. I.; SERGEEV, D. A.; VDOVIN, M. I.; BAIDAKOV, G. A.: Average velocity field of the air flow over the water surface in a laboratory modeling of storm and hurricane conditions in the ocean. Izvestiya, Atmospheric and Oceanic Physics. 2014, Vol. 50, Issue 4, pp 399–410. 1210.1134/S000143381404015X

ORIGINAL_ARTICLEThe pursuit of increased steam turbine power output leads to a design of low pressure stages with large diameters, featuring long and thin blades. The interaction of the structure with flow may induce vibrations, leading to a reduced operational life of the machine due to material fatigue. This work introduces a mathematical model of fluid-structure interaction, intended for the investigation of flow-induced turbine blade vibrations. At present, it is applied to a simplified test case of an isolated airfoil. The flow model is based on 2D Euler equations in Arbitrary Lagrangian-Eulerian formulation, discretized by the Finite Volume Method with a second-order accurate AUSM+-up scheme. The structure is modelled as a solid body with one rotational and one translational degree of freedom. The solution is realized iteratively by a time-marching method with a two-way fluid-structure coupling. In each iteration the airfoil surface pressure is integrated to determine the forces and the torsional moment driving its motion. The position of the airfoil in the next time step is obtained and the flow is resolved on a newly recreated mesh. The results of the present model are validated by comparison with experimental data and with numerical results of other models.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_04.pdf2019-06-30395710.15240/tul/004/2019-1-004AeroelasticityTurbineAirfoilVibrationsArbitrary Lagrange-EulerFinite volume methodMarekPátýmarek.paty@fs.cvut.cz1Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Technical Mathematics, Center of AdvancedAUTHORJanHalamajan.halama@fs.cvut.cz2Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Technical Mathematics, Center of AdvancedAUTHORCOLLAR, A. R.: The Expanding Domain of Aeroelasticity. The Aeronautical Journal. 1946, Vol. 50, Issue 428, pp. 613–636.110.1017/S0368393100120358WICK, T.: Coupling of fully Eulerian and arbitrary Lagrangian-Eulerian methods for fluid-structure interaction computations. Computational Mechanics. 2013, Vol. 52, Issue 5, pp. 1113–1124.210.1007/s00466-013-0866-3RZĄDKOWSKI, R.; GNESIN, V.: 3-D inviscid self-excited vibrations of a blade row in the last stage turbine. Journal of Fluids and Structures. 2007, Vol. 23, Issue 6, pp. 858–873.310.1016/j.jfluidstructs.2006.12.003PETRIE-REPAR, P.; MAKHNOV, V.; SHABROV, N.; SMIRNOV, E.; GALAEV, S.; ELISEEV, K.: Advanced Flutter Analysis of a Long Shrouded Steam Turbine Blade. In: ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. 2014, Paper No. GT2014-26874. ISBN 978-0-7918-4577-6.410.1115/GT2014-26874SLONE, A. K.; PERICLEOUS, K.; BAILEY, C.; CROSS, M.; BENNETT, C.: A finite volume unstructured mesh approach to dynamic fluid–structure interaction: an assessment of the challenge of predicting the onset of flutter. Applied Mathematical Modelling. 2004, Vol. 28, Issue 2, pp. 211–239.510.1016/S0307-904X(03)00142-2KAMAKOTI, R.; SHYY, W.: Fluid–structure interaction for aeroelastic applications. Progress in Aerospace Sciences. 2004, Vol. 40, Issue 8, pp. 535–558.610.1016/j.paerosci.2005.01.001SVÁČEK, P.; FEISTAUER, M.; HORÁČEK, J.: Numerical simulation of flow induced airfoil vibrations with large amplitudes. Journal of Fluids and Structures. 2007, Vol. 23, Issue 3, pp. 391–411. 710.1016/j.jfluidstructs.2006.10.005CORRAL, R.; JAVIER, C.: Development of an Edge-Based Harmonic Balance Method for Turbomachinery Flows. In: ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. 2011, Paper No. GT2011-45170. ISBN 978-0-7918-5467-9. 810.1115/GT2011-45170GNESIN, V. I.; KOLODYAZHNAYA, L. V.; RZADKOWSKI, R.: A numerical modelling of stator–rotor interaction in a turbine stage with oscillating blades. Journal of Fluids and Structures. 2004, Vol. 19, Issue 8, pp. 1141–1153. 910.1016/j.jfluidstructs.2004.07.001MASSEREY, P.-A.; McBEAN, I.; LORINI, H. Analysis and improvement of vibrational behaviour on the ND37 A last stage blade. VGB Powertech Journal. 2012, Vol. 92, pp. 42–48.10THEODORSEN, T.: Report No. 496: General Theory of Aerodynamic Instability and the Mechanism of Flutter. 1935. Technical Report. NASA Technical Documents.11PERRY, B.: Re-Computation of Numerical Results Contained in NACA Report No. 496. 2015. Technical Report. NASA Langley Research Center; Hampton, Virginia, United States.12DOI, H.; ALONSO, J. J.: Fluid/Structure Coupled Aeroelastic Computations for Transonic Flows in Turbomachinery. In: ASME Turbo Expo 2002: Power for Land, Sea, and Air. 2002, Paper No. GT2002-30313. ISBN 0-7918-3609-6. eISBN 0-7918-3601-0. 1310.1115/GT2002-30313NING, W.; HE, L.: Computation of Unsteady Flows Around Oscillating Blades Using Linear and Nonlinear Harmonic Euler Methods. Journal of Turbomachinery. 1998, Vol. 120, Issue 3, pp. 508–514.1410.1115/1.2841747SANCHES, R. A. K.; CODA, H. B.: On fluid–shell coupling using an arbitrary Lagrangian–Eulerian fluid solver coupled to a positional Lagrangian shell solver. Applied Mathematical Modelling. 2014, Vol. 38, Issue 14, pp. 3401–3418.1510.1016/j.apm.2013.11.025DONEA, J.; GIULIANI, S.; HALLEUX, J. P.: An arbitrary lagrangian-eulerian finite element method for transient dynamic fluid-structure interactions. Computer Methods in Applied Mechanics and Engineering. 1982, Vol. 33, Issues 1–3, pp. 689–723.1610.1016/0045-7825(82)90128-1BOFFI, D.; GASTALDI, L.: Stability and geometric conservation laws for ALE formulations. Computer Methods in Applied Mechanics and Engineering. 2004, Vol. 193, Issues 42–44, pp. 4717–4739.1710.1016/j.cma.2004.02.020SAKSONO, P. H.; DETTMER, W. G.; PERIĆ, D.: An adaptive remeshing strategy for flows with moving boundaries and fluid–structure interaction. International Journal for Numerical Methods in Engineering. 2007, Vol.71, Issue 9, pp. 1009–10501810.1002/nme.1971MAY, M.; MAUFFREY, Y.; SICOT, F.: Numerical flutter analysis of turbomachinery bladings based on time-linearized, time-spectral and time-accurate simulations. In: Proceedings of IFASD 2011 – 15th International Forum on Aeroelasticity and Structural Dynamics. 2011, Paper No. IFASD-2011-080.19HÖHN, W.: Numerical Investigation of Blade Flutter at or Near Stall in Axial Turbomachines. In: ASME Turbo Expo 2001: Power for Land, Sea, and Air. 2001, Paper No. 2001-GT-0265. ISBN 978-0-7918-7853-8.2010.1115/2001-GT-0265STOREY, P.: Holographic Vibration Measurement of a Rotating Fluttering Fan. In: Proceedings of AIAA/SAE/ASME 18th Joint Propulsion Conference. 1982.2110.2514/6.1982-1271SLONE, A. K.; BAILEY, C.; CROSS, M.: Dynamic Solid Mechanics Using Finite Volume Methods. Applied Mathematical Modelling. 2003, Vol. 27, Issue 2, pp. 69–87.2210.1016/S0307-904X(02)00060-4SLONE, A. K.; PERICLEOUS, K.; BAILEY, C.; CROSS, M.: Dynamic fluid–structure interaction using finite volume unstructured mesh procedures. Computers & Structures. 2002, Vol. 80, Issues 5–6, pp. 371–390.2310.1016/S0045-7949(01)00177-8HONZÁTKO, R.: Numerical Simulations of Incompressible Flows with Dynamical and Aeroelastic Effects. PhD thesis. Czech Technical University in Prague, 2007.24LIOU, M.-S.; STEFFEN Jr., Ch. J.: A New Flux Splitting Scheme. Journal of Computational Physics. 1993, Vol. 107, Issue 1, pp. 23–39.2510.1006/jcph.1993.1122LIOU, M.-S.: A sequel to AUSM, Part II: AUSM+ -up for all speeds. Journal of Computational Physics. 2006, Vol. 214, Issue 1, pp. 137–170.2610.1016/j.jcp.2005.09.020SMITH, R. W.: AUSM(ALE): A Geometrically Conservative Arbitrary Lagrangian– Eulerian Flux Splitting Scheme. Journal of Computational Physics. 1999, Vol. 150, Issue 1, pp. 268–286. 2710.1006/jcph.1998.6180LIOU, M.-S.: A Sequel to AUSM: AUSM+ . Journal of Computational Physics. 1996, Vol. 129, Issue 2, pp. 364–382.2810.1006/jcph.1996.0256DARRACQ, D.; CHAMPAGNEUX, S.; CORJON, A.: Computation of Unsteady Turbulent Airfoil Flows with an Aeroelastic AUSM+ Implicit Solver. In: Proceedings of 16th AIAA Applied Aerodynamics Conference. 1998.2910.2514/6.1998-2411HIRSCH, Ch.: Numerical Computation of Internal and External Flows. The Fundamentals of Computational Fluid Dynamics. Elsevier, 2007. ISBN 978-0-7506- 6594-0.3010.1016/B978-0-7506-6594-0.X5037-1BENETKA, J.: Měření kmitajíıcího profilu v různě vysokých měřících prostorech. 1981. Technical Report Z-2610/81. Aeronautical Research and Test Institute, Prague, Letňany.31LUCHTA, J.: Sborník charakteristik profilů křídel. 1955. Technical Report 1669/55. VTA AZ, Brno.32BENETKA, J.; KLADRUBSKÝ, J.; VALENTA, R.: Measurement of NACA 0012 profile in a slotted measurement section. 1998. Technical Report R-2909/98. Aeronautical Research and Test Institute, Prague, Letňany.33TRIEBSTEIN, H.: Steady and unsteady transonic pressure distributions on NACA 0012. Journal of Aircraft. 1986, Vol. 23, Issue 3, pp. 213–219.3410.2514/3.45291

ORIGINAL_ARTICLEThere have been tried many types of micro-capillaries, square or round and with different sizes of inner diameter. In which a cavitation bubble was created. The purpose of these experiments was to observe the velocity of the shock wave just after the initial cavitation bubble the rebound ones inside the micro-capillary and outside the micro-capillary. The most of the method was spark to induced superheat limit of liquid. Here we used the laser-induced breakdown (LIB) method. There were described the set cavitation setting that affects the stability and size of the bubble. We used here shadowgraphy setup for visualized the cavitation bubbles and shock wave with a camera. There were observed time development of the shock wave velocity; the velocity of the initial shock wave inside the micro-capillary was higher than the shock velocity outside the micro-capillary.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_05.pdf2019-06-30586710.15240/tul/004/2019-1-005ShockwaveCavitationExplosion bubbleLaser-induced breakdown (LIB)PetrSchovanecpetr.schovanec@tul.cz1Technical University of Liberec, Department of Physical Measurement, The Institute for Nanomaterials, Advanced Technology and InAUTHORWalterGaren2 Hochschule Emden/Leer, University of Applied Sciences, Institute for Laser and OpticsAUTHORSandraKoch3 Hochschule Emden/Leer, University of Applied Sciences, Institute for Laser and OpticsAUTHORWalterNeu4 Hochschule Emden/Leer, University of Applied Sciences, Institute for Laser and OpticsAUTHORPetraDančová5 Technical University of Liberec, Faculty of Mechanical Engineering, Department of Power Engineering EquipmentAUTHORDarinaJašíková6Technical University of Liberec, Department of Physical Measurement, The Institute for Nanomaterials, Advanced Technology and InAUTHORMichalKotek7Technical University of Liberec, Department of Physical Measurement, The Institute for Nanomaterials, Advanced Technology and InAUTHORVáclavKopecký8Technical University of Liberec, Department of Physical Measurement, The Institute for Nanomaterials, Advanced Technology and InAUTHORJAŠÍKOVÁ, D.; SCHOVANEC, P.; KOTEK, M.; KOPECKÝ, V.: Comparison of cavitation bubbles evolution in viscous media. EPJ Web of Conferences. 2018, Vol. 180, Paper No. 02038.110.1051/epjconf/201818002038JAŠÍKOVÁ, D.; SCHOVANEC, P.; KOTEK, M.; MÜLLER, M.; KOPECKÝ, V.: Comparison of ultrasound and LIB generated cavitation bubble. EPJ Web of Conferences. 2017, Vol. 143, Paper No. 02044. 210.1051/epjconf/201714302044JAŠÍKOVÁ, D.; SCHOVANEC, P.; KOTEK, M.; MÜLLER, M.; KOPECKÝ, V.: Experimental setup for laser-induced breakdown in aqueous media. In: Proceedings of Optics and Measurement International Conference 2016. SPIE 2016, Vol. 10151, Paper No. 101510L.310.1117/12.2260998JAŠÍKOVÁ, D.; KOTEK, M.; MÜLLER, M.; KOPECKÝ, V.: Single cavitation bubble interaction close to hydrophobic surface. International Journal of Mechanics. 2017, Vol. 11, pp. 73–81. Available from WWW: https://www.researchgate.net/publication/316964593_Single_cavitation_bubble_interact ion_close_to_hydrophobic_surface4JAŠÍKOVÁ, D.; MÜLLER, M.; KOTEK, M.; KOPECKÝ, V.: The synchronized force impact measurement and visualization of single cavitation bubble generated with LIB. International Journal of Mechanics. [online]. 2015, Vol. 9, pp. 76–82. Available from WWW: https://www.researchgate.net/publication/281940252_The_synchronized_force_impact_ measurement_and_visualization_of_single_cavitation_bubble_generated_with_LIB5BRENNEN, Ch. E.: Cavitation and Bubble Dynamics. Cambridge University Press, 2013. Online ISBN 9781107338760. 610.1017/CBO9781107338760KENNEDY, P. K.; HAMMER, D. X.; ROCKWELL, B. A.: Laser-induced breakdown in aqueous media. Progress in Quantum Electronics. 1997, Vol. 21, Issue 3, pp. 155– 248. 710.1016/S0079-6727(97)00002-5BRUJAN, E.-A.; NAHEN, K.; SCHMIDT, P.; VOGEL, A.: Dynamics of laser-induced cavitation bubbles near an elastic boundary. Journal of Fluid Mechanics. 2001, Vol. 433, pp. 251–281.810.1017/S0022112000003347LAUTERBORN, W.; KURZ, T.; METTIN, R.; KOCH, P.; KRÖNINGER, D.; SCHANZ, D.: Acoustic Cavitation and Bubble Dynamics. Archives of Acoustics. 2008, Vol. 33, Issue 4, pp. 609–617. Print ISSN 0137-5075. Online ISSN 2300-262X.9SHIMA, A.; TOMITA, Y.: The behavior of a spherical bubble near a solid wall in a compressible liquid. Ingenieur-Archiv. 1981, Vol. 51, Issue 3–4, pp 243–255. 1010.1007/BF00535992VOGEL, A.; BUSCH, S.; PARLITZ, U.: Shock wave emission and cavitation bubble generation by picosecond and nanosecond optical breakdown in water. The Journal of the Acoustical Society of America. 1996, Vol. 100, Issue 1.1110.1121/1.415878VOGEL, A. et al.: Energy balance of optical breakdown in water at nanosecond to femtosecond time scales. Applied Physics B: Lasers and Optics. 1999, Vol. 68, Issue 2, pp. 271–280. 1210.1007/s003400050617KAI, Y.; MEYERER, B.; GAREN, W.; TEUBNER, U.: Experimental investigation of laser generated shock waves and the onset of evaporation in a mini-shock glass tube filled with water. In: ISIS21, the 21st International Shock Interaction Symposium. Riga, Latvia, 2014, pp. 168-170.13GAREN, W.; HEGEDŰS, F.; KAI, Y.; KOCH, S.; MEYERER, B.; NEU, W.; TEUBNER, U.: Shock wave emission during the collapse of cavitation bubbles. Shock Waves. 2016; Vol. 26, Issue 4, pp 385–3941410.1007/s00193-015-0614-z

ORIGINAL_ARTICLEA Mach-Zehnder interferometer system combined with a high-speed camera is applied for a shock train in a constant-area straight duct to clarify its unsteady characteristic in which just upstream of the shock train the freestream Mach number is 1.44, the unit Reynolds number is 4.97 × 107 m-1, and the boundary layer thickness is 0.472 mm. An instantaneous two-dimensional density field in the shock train is quantitatively obtained with high spatial resolution. The present Mach-Zehnder interferometer system is found to be effective for unsteady density measurements in shock-dominated flows in a two-dimensional duct. The oscillatory characteristic of each shock in the shock train is demonstrated by power spectral analysis of the unsteady density field.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_06.pdf2019-06-30687710.15240/tul/004/2019-1-006Shock trainSupersonic flowUnsteady flowMach-Zehnder interferometerDensity measurementTaishiTakeshitay7mba011@eng.kitakyu-u.ac.jp1The University of Kitakyushu, Faculty of Environmental Engineering, Department of Mechanical Systems EngineeringAUTHORShinichiroNakao2The University of Kitakyushu, Faculty of Environmental Engineering, Department of Mechanical Systems EngineeringAUTHORYoshiakiMiyazato3The University of Kitakyushu, Faculty of Environmental Engineering, Department of Mechanical Systems EngineeringAUTHORMATUO, K.; MIYAZATO, Y.; KIM, H.-D.: Shock train and pseudo-shock phenomena in internal gas flows. Progress in Aerospace Sciences. 1999, Vol. 35, Issue 1, pp. 33– 100.110.1016/S0376-0421(98)00011-6GNANI, F.; ZARE-BEHTASH, H.; KONTIS, K.: Pseudo-shock waves and their interactions in high-speed intakes. Progress in Aerospace Sciences. 2016, Vol. 82, pp. 36–56.210.1016/j.paerosci.2016.02.001LEE, H. J.; LEE, B. J.; KIM, S. D.; JEUNG, I.-S.: Investigation of the pseudo-shock wave in a two-dimensional supersonic inlet. Journal of Visualization. 2010, Vol. 13, Issue 1, pp. 25–32.310.1007/s12650-009-0008-3QIN, B.; CHANG, J.; JIAO, X.; BAO, W.; YU, D.: Numerical investigation of the impact of asymmetric fuel injection on shock train characteristics. Acta Astronautica. 2014, Vol. 105, Issue 1, pp. 66–74.410.1016/j.actaastro.2014.08.025XU, K.; CHANG, J.; ZHOU, W.; YU, D.: Mechanism of shock train rapid motion induced by variation of attack angle. Acta Astronautica. 2017, Vol. 140, pp. 18–26.510.1016/j.actaastro.2017.08.009LI, N.; CHANG, J.; YU, D.; BAO, W.; SONG, Y.: Mathematical Model of Shock-Train Path with Complex Background Waves. Journal of Propulsion and Power. Vol. 33, Issue 2, pp. 468–478.610.2514/1.B36234DENG, R.; JIN, Y.; KIM, H. D.: Numerical simulation of the unstart process of dualmode scramjet. International Journal of Heat and Mass Transfer. 2017, Vol. 105, pp. 394–400.710.1016/j.ijheatmasstransfer.2016.10.004SU, W.-Y.; CHEN, Y.; ZHANG, F.-R.; TANG, P.-P.: Control of pseudo-shock oscillation in scramjet inlet-isolator using periodical excitation. Acta Astronautica. 2018, Vol. 143, pp. 147–154.810.1016/j.actaastro.2017.10.040JIAO, X.; CHANG, J.; WANG, Z.; YU, D.: Periodic forcing of a shock train in a scramjet inlet-isolator at overspeed condition. Acta Astronautica. 2018, Vol. 143, pp. 244–254.910.1016/j.actaastro.2017.12.005XIONG, B.; WANG, Z.-G.; FAN, X.-Q.; WANG, Y.: Experimental study on the flow separation and self-excited oscillation phenomenon in a rectangular duct. Acta Astronautica. 2017, Vol. 133, pp. 158–165.1010.1016/j.actaastro.2017.01.009XIONG, B.; FAN, X.-Q.; WANG, Y.; TAO, Y.: Experimental Study on Self-Excited and Forced Oscillations of an Oblique Shock Train. Journal of Spacecraft and Rockets. 2018, Vol. 55, Issue 3, pp. 640–647.1110.2514/1.A33973XIONG, B.; WANG, Z.-G.; FAN, X.-Q.; WANG, Y.: Response of Shock Train to High-Frequency Fluctuating Backpressure in an Isolator. Journal of Propulsion and Power. 2017, Vol. 33, Issue 6, pp. 1–9.1210.2514/1.B36291TAKEDA, M.; INA, H.; KOBAYASHI, S.: Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry. Journal of the Optical Society of America. 1982, Vol. 72, Issue 1, pp. 156–160.1310.1364/JOSA.72.000156YAGI, S.; INOUE, S.; NAKAO, S.; ONO, D.; MIYAZATO, Y.: Optical Measurements of Shock Waves in Critical Nozzles at Low Reynolds Numbers. Journal of Flow Control, Measurement & Visualization. 2017, Vol. 5, Issue 2, pp. 36–50.1410.4236/jfcmv.2017.52003TAKESHITA, T.; TAKANO, H.; ONO, D.; NAKAO, S.; MIYAZATO, Y.: Rainbow Schlieren visualization of shock trains in rectangular ducts. In: Proceedings of the 23rd International Symposium on Air Breathing Engines (ISABE 2017). [online]. 2017. Available from WWW: https://www.isabe.org/15

ORIGINAL_ARTICLESeveral control methods for the flow around a bluff body have been proposed in previous studies. One such method is the forced reattachment method, which is a type of separated shear layer control that uses a small rod. The small rod is placed in the optimal position on the shear layer from a circular cylinder, thus dividing the shear layer into upper and lower parts. The upper shear layer is supported and elongated by the small rod, and the lower shear layer reattaches and adheres to the rear side of the cylinder. A large stagnant region forms behind the cylinder. This method reduces drag and generates a lift, and is promising for bluff body flow control. However, the forced reattachment phenomenon occurs only under certain conditions. The aim of the present study was to clarify the rod position and diameter required for forced reattachment.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_07.pdf2019-06-30788610.15240/tul/004/2019-1-007Circular cylinderFlow controlDrag reductionFluid forceFlow visualizationTakayukiTsutsuitsutsui@nda.ac.jp1National Defense Academy of Japan, Department of Mechanical EngineeringAUTHORIGARISHI, T.; TSUTSUI, T.: Flow Control around a Circular Cylinder by a Small Cylinder. In: Proceedings of the 11th Australasian Fluid Mechanics Conference. Hobart, Australia, 1992, pp. 519–522.1IGARASHI, T.; TSUTSUI, T.: Flow Force Acting on a Circular Cylinder Controlled by a Small Rod. In: Proceedings of the 3rd JSME-KSME Fluids Engineering Conference. Sendai, Japan, 1994, pp. 571–576.2TSUTSUI, T.; IGARASHI, T.; KAMEMOTO, K.: Interactive flow around two circular cylinders of different diameters at close proximity. Experiment and numerical analysis by vortex method. Journal of Wind Engineering and Industrial Aerodynamics. 1997, Volumes 69–71, pp. 279–291.310.1016/S0167-6105(97)00161-XTSUTSUI, T.; IGARASHI, T.: Flow control around a circular cylinder by a small cylinder (Properties of reattachment jet). In: Proceedings of the 3rd ASME-JSME Joint Fluids Engineering Conference. San Francisco, California, FEDSM'99-6943, 1999.4TSUTSUI, T.: Instantaneous fluid force acting on a circular cylinder control by a small rod. EPJ Web of Conferences. 2018, Vol. 180, Paper No. 02110. 510.1051/epjconf/201818002110

ORIGINAL_ARTICLEGround-source heat pumps are a sustainable technology to increase the use of renewable energy sources. In order to exploit the maximum potential of near-surface geothermal energy, optimization concepts for borehole heat exchanger systems that combine heating and cooling are being developed at the University of Applied Sciences Zittau/Görlitz. The objectives of this research are not only the reduction of primary energy consumption but also the development of predictive models for system planning, especially with respect to the influence of groundwater. Additionally, constructive and economic aspects of borehole heat exchanger systems are evaluated.https://acc-ern.tul.cz/archiv/PDF/ACC_2019_1_08.pdf2019-06-30889210.15240/tul/004/2019-1-008Near-surface geothermal energyHeat pumpBorehole heat exchangerRenewable energy Seasonal thermal energy storageGroundwater flowAxelGerschelaxel.gerschel@hszg.de1Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORMarkusHaackm.haack@hszg.de2Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORPrasanthSubramani3Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORLukasStöckmann4Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORThomasSchäfer5Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORTomWalter6Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORTinoSchütte7Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORJörnKrimmling8Hochschule Zittau/Görlitz, University of Applied Sciences, Fakultät Wirtschaftswissenschaften und WirtschaftsingenieurwesenAUTHORBUNDESMINISTERIUM FÜR WIRTSCHAFT UND ENERGIE (2015): Energieeffizienzstrategie Gebäude. Brochure. 146 pp. Berlin.1BAYER, P.; de PALY, M.; BECK, M. (2014): Strategic optimization of borehole heat exchanger field for seasonal geothermal heating and cooling. Applied Energy. Vol. 136, pp. 445–453.210.1016/j.apenergy.2014.09.029KÖLBEL, T. (2010): Grundwassereinfluss auf Erdwärmesonden: Geländeuntersuchungen und Modellrechnungen. Dissertation. 146 pp. Karlsruher Institute of Technology.3BAUER, D. (2011): Zur thermischen Modellierung von Erdwärmesonden und Erdsonden-Wärmespeichern. Dissertation. 121 pp. University of Stuttgart.4KRIMMLING, J. et al. (2015): Speichervorgänge im Umfeld vertikaler Erdsonden von Wärmepumpen. HLH. Vol. 66 (1): 19 pp.5