The study presents evaluation of optical measurements of the air flow field near the fluttering profile NACA0015 with two-degrees of freedom, Mach number of the flutter occurence were M = 0.21 and M = 0.45. Aerodynamic forces (drag and lift components) were evaluated independently on the upper and lower surfaces of the profile. Using the mentioned decomposition, the new information about mechanism of flutter properties was obtained. The forces on the upper and lower surfaces are phase shifted and are partially eliminated as a result of the circulation around the profile. The cycle changes of these forces cause the permanent energy contribution from the airflow to the vibrating system. and Obsahuje seznam literatury
The paper presents the preliminary results of the analysis of two archival SAR datasets acquired by ERS-1/2 satellites of the same area of Roznow Lake in Southern Poland. Both datasets cover the same period of 8 years (1992 - 2000) and refers to the same area by the 50% of overlap between the neighbouring satellite tracks. The main purpose of this analysis was to derive the overlapping data about deformation velocity calculated using PSI (Persistent Scatterers Interferometry). The presented PSI results refer to PS (Persistent Scatterers) located on active landslides and therefore representing landslide movement. In Polish Carpathians, due to sparse urbanization, vegetation and rough relief the obtained PS density is usually not very high and generally difficult to interpret. The application of two overlapping datasets, where both of them observe the same phenomena, allow to cross-validate the data by identification of common PS points. For two datasets acquired from different tracks, usually many PS are not common and occur at different locations. Such situation could be explained by the difference between the incidence angles for both acquisitions. In a case of two tracks and therefore different terrain objects might act as PS. By joining the PS point sets from such neighbouring tracks the density of PS could be significantly increased. In order to perform a PSI analysis of Roznow Lake the data acquired from 179 and 408 tracks have been used and a few hundred of PS were obtained from PSI processing. For both tracks similar deformations velocity were obtained within a range of +/- 6 mm/yr. The PS points on active landslides are usually related to the buildings (walls, roofs) and roads affected usually by high risk., Zbigniew Perski, Andrzej Borkowski, Tomasz Wojciechowski and Antoni Wójcik., and Obsahuje bibliografii
Secondary deformations are ground movements occurring in areas of ceased underground mining. These are associated with delayed readjustment of rock mass resulting in subsidence, discontinuous deformations (sinks, cracks, etc.) due to destruction of underground, usually shallow, workings, and elevation of ground surface in response of rock mass to rising groundwater levels following the end of mine water drainage. Comparative analysis of secondary deformations in two former mining areas in the first period after cessation of underground hard coal mining is the subject of this study. We used ERS-1/2 and Envisat satellite radar interferometry data processed with PSInSAR technique and GIS to map vertical (in satellite’s line of sight, LOS) movements of the surface and analyse them in relation to location of coal fields and underground water table rise. In the study, two areas have been compared, the Ostrava city in the Czech part of the Upper Silesian Basin and the Wałbrzych Coal Basin in Poland. The results of analyses based on the results of PSInSAR processing between 1995 and 2000 for the Wałbrzych site indicate uplift (up to +12 mm/year) in closed parts of coal fields and subsidence (up to -8 mm/year) in areas of declining mining. Results of PSInSAR analysis over the Ostrava site indicate decaying subsidence after mine closures in the rate of up to -6 mm/year during 1995-2000. Residual subsidence and gentle uplift have been partly identified at surroundings of closed mines in Ostrava from 2003-2010 Envisat data. In Wałbrzych gentle elevation has been determined from 2002 to 2009 in areas previously subsiding. and Blachowski Jan, Jiránková Eva, Lazecký Milan, Kadlečík Pavel, Milczarek Wojciech.
This work describes a quantitative evaluation of interference patterns applied for testing of optical surfaces. The proposed method is based on the correlation between measured and virtual (nominal) interferograms and employment of mathematical nonlinear optimization. In contrast to most of common phase evaluation methods the proposed method does not need a detailed analysis of the interference patterns and phase unwrapping. The deviation of the measured surface from its nominal shape is modeled using a suitable function with unknown parameters, which are calculated by optimization of the merit function. The merit function is the correlation coefficient between measured and nominal interferogram, which characterizes the similarity of both interferograms. The functionality of the method was verified both by computer simulations and practical experiments. The method is applicable for the interferometric testing of flat, spherical and aspherical surfaces. and V práci je popsána metoda kvantitativního vyhodnocování interferenčního pole při kontrole tvaru optických ploch. Navržená metoda využívá korelace mezi měřeným a virtuálním (nominálním) interferogramem a matematických metod nelineární optimalizace. Na rozdíl od většiny běžně používaných metod nevyžaduje navržená metoda detailní analýzu interferenčního pole a odstranění nespojitostí fázových hodnot (tzv. phase unwrapping). Odchylka kontrolované plochy od jejího nominálního tvaru je modelována pomocí vhodné funkce s neznámými parametry, které jsou získány optimalizací meritní funkce. Za meritní funkci je zvolen korelační koeficient mezi měřeným a virtuálním (nominálním) interferogramem, který charakterizuje podobnost obou interferogramů. Funkčnost metody byla ověřena jak pomocí počítačových simulací, tak i na reálných případech měření. Metoda je použitelná pro interferometrickou kontrolu rovinných, sférických i asférických ploch.
The paper describes the results of Persistent Scatterers Interferometry (PSI) study of Sambia peninsula. The idea of this work was to verify the hypothesis whether any terrain surface deformation that occur in Sambia area, could be interpreted as related to tectonic processes. Moreover, if any movements are detected what is their relationship to the 21 September 2004 earthquake? To answer these questions SAR (Synthetic Aperture Radar) data from European satellites ERS-1 and ERS-2 acquired from 1992 to 2001 were processed with interferometric techniques to archive independent data about terrain surface deformation. The obtained results - 4 sets of PS (Persistent Scatterers) points with calculated movement velocities (mm/yr) according to linear model were compared with published results of terrestrial measurements. The analysis of PS results confirms the occurrence of terrain deformations of tectonic origin of few mm/yr. The distribution of deformation velocities suggest its relationship to the recent activity occurring along two E-W trending seismoactive sub-zones located along Pregola river valley and possibly in the northern coast of Sambia Peninsula., Zbigniew Perski and Marek Mróz., and Obsahuje bibliografii
This paper deals with issues related to convenient monitoring of subsidence due to longtime mining activities of Czech Karviná Mine: Lazy plant, using satellite SAR interferometry (InSAR) techniques. It maintains approaches for optimizations of differential InSAR, especially including available filtering possibilities. It was realized that current SAR satellites were not able to appropriately evaluate deep subsidence as it occurs in Czech mining sites. Other issues are related to the presence of dense vegetation. Data from previous and only available L-band SAR satellite ALOS demonstrates its high potential in this area of interest. However, only a few acquisitions are available of the mining site disallowing usage for purposes of continuous monitoring of subsidence in the area. Processing results of InSAR techniques of the Lazy plant are presented in this paper., Milan Lazecký and Eva Jiránková., and Obsahuje bibliografii
This paper presents preliminary results of the application of Persistent Scatterers Interferometry (PSI) supported with detailed field landslide mapping. The research was focused on the areas located near the towns Rabka Zdroj and Jordanow located in southern-central Poland where detailed landslide mapping campaigns were preformed in the summer of 2009. According to the field experience the average spatial density of landslide occurrence in both areas is up to 3 landslides/sq km. The application of various Synthetic Aperture Radar (SAR) interferometry techniques on the above-mentioned areas was very difficult due to the very rough topography, vegetation and forest cover, and the long season with the snow cover. Following previous successful studies on other rural areas, PSI technique was therefore applied. Field work has been carried out within the frame of a national project launched in 2008 aimed to create a detailed database of all landslides in Poland. The areas where landslide problems are extremely important are the Polish Carpathians. As in previous experiments on a sparse urbanized area we noticed that it is still possible to successfully detect a number of persistent scatterers but, the interpretation of the associated deformation is difficult. However, based on cartographic data collected during the field mapping campaign it is possible to significantly improve analysis and interpretation of PSI results., Zbigniew Perski, Tomasz Wojciechowski and Andrzej Borkowski., and Obsahuje bibliografii
Research and development of interferometric systems for coordinate and multiaxis measuring are the goal of a common collaborative project involving the Institute of Scientific Instruments, Czech Academy of Sciences and Meopta - optika, s.r.o. The common effort is oriented to applications with the highest demands for precision in the dimensional metrology and nanometrology. The concept of the system represents a modular family of components configurable for various arrangements especially for coordinate measurements in nanotechnology and measurement of topography of surfaces. Meopta - optika, s.r.o. contributes to the project through development of new technology of production of optical components. We present here compact interferometric units designed for measurement by reflection from flat mirror. and Výzkum a vývoj interferometrických odměřovacích systémů pro souřadnicové a víceosé odměřování je náplní společného projektu, v němž spolupracují Ústav přístrojové techniky, Akademie věd České republiky, v.v.i. a podnik Meopta - optika, s.r.o. Společné snažení směřuje k aplikacím s nejvyššími nároky na přesnost v dimenzionální metrologii a nanometrologii. Zvolená koncepce systému představuje modulární rodinu komponent konfigurovatelnou pro různá uspořádání, zvláště pro víceosá měření v nanotechnologiích a měřeních topografie povrchů. Meopta - optika, s.r.o. přispívá především vývojem nové technologie výroby optických prvků rovinné optiky. Zde prezentujeme kompaktní interferometrické jednotky navržené pro interferometrické měření odrazem od rovinného zrcadla.