Wyniki wyszukiwania - BazTech

1

Reflection of PlaneWaves at Micropolar Piezothermoelastic Half-space

Kumar R., Sharma N., Lata P., Marin M.

Computational Methods in Science and Technology

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2018

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Vol. 24, No. 2

113--124

EN

A problem of reflection at a free surface of micropolar orthotropic piezothermoelastic medium is discussed in the present paper. It is found that there exist five type plane waves in micropolar orthotropic piezothermoelastic medium, namely quasi longitudinal displacement wave (quasi LD wave), quasi thermal wave (quasi T wave), quasi CD-I, quasi CD-II wave and electric potential wave (PE wave). The amplitude ratios corresponding to reflected waves are obtained numerically. The effect of angle of incidence and thermopiezoelectric interactions on the reflected waves are studied for a specific model. Some particular cases of interest are also discussed.

2

Experimental study of the flow around two finite square cylinders

Sohankar A., Abbasi M., Nili-Ahmadabadi M., Alam M. M., Zafar F.

Archives of Mechanics

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2018

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Vol. 70, nr 5

457--480

EN

An experimental investigation is conducted on the air flow past two wallmounted finite length side-by-side square cylinders, each of the aspect ratio AR = 7. The cylinder center-to-center spacing ratio T/d is varied from 2 to 6, where d is the side-width of the cylinder. The cylinders are placed at three incidence angles with respect to the freestream velocity, i.e. both cylinders at zero incidence angle (case I), both cylinders at 45° incidence angle (case II), and one cylinder at zero incidence angle with the other at 45° incidence angle (case III). The pressure distributions on the surfaces of the cylinders are measured at Reynolds numbers of 5.9 × 104–8.1 × 104. In addition, the flow structures are visualized in a smoke wind tunnel at the Reynolds number of 2 × 103. Depending on the flow characteristics, four flow structures are identified at the mid-height of the cylinders, namely the asymmetric flow, antiphase shedding flow, leading-edge separated flow and wedge flow. The sectional drag near the bottom is more sensitive to T/d than that near the top. The sectional drag coefficient measured at 0.5d below the mid-span can represent the surface-averaged drag coefficient on the entire cylinder.

3

A method of directly extracting multiwave angle-domain common-image gathers

Han J., Wang Y.

Acta Geophysica

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2017

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Vol. 65, no. 5

1009--1017

EN

Angle-domain common-image gathers (ADCIGs) can provide an effective way for migration velocity analysis and amplitude versus angle analysis in oil-gas seismic exploration. On the basis of multi-component Gaussian beam prestack depth migration (GB-PSDM), an alternative method of directly extracting multiwave ADCIGs is presented in this pa-per. We first introduce multi-component GB-PSDM, where a wavefield separation is proceeded to obtain the separated PP- and PS-wave seismic records before migration imaging for multiwave seismic data. Then, the principle of extracting PP- and PS-ADCIGs using GB-PSDM is pre-sented. The propagation angle can be obtained using the real-value travel time of Gaussian beam in the course of GB-PSDM, which can be used to calculate the incidence and reflection angles. Two kinds of ADCIGs can be extracted for the PS-wave, one of which is P-wave incidence ADCIGs and the other one is S-wave reflection ADCIGs. In this paper, we use the incident angle to plot the ADCIGs for both PP- and PS-waves. Finally, tests of synthetic examples show that the method introduced here is accu-rate and effective.

4

Sprawność kolektora cieczowego w funkcji kąta padania promieniowania słonecznego

Latała H.

Inżynieria Rolnicza

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2006

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R. 10, nr 11(86)

299-307

PL

W prezentowanej pracy przedstawiono wyniki przeprowadzonych badań dotyczące określenia sprawności kolektora słonecznego w funkcji kąta padania promieniowania słonecznego. Badania eksperymentalne wykonano na specjalnie przygotowanym stanowisku, które umożliwiało monitorowanie istotnych parametrów oraz ich archiwizację. Analizowano zarówno wartość dostępnego strumienia promieniowania słonecznego jak i temperatury czynnika grzewczego na wejściu i wyjściu układu kolektorów oraz temperaturę otoczenia. Ciepło użyteczne z kolektorów wyznaczono z równania Hottela-Whilliera-Bilissa, które uwzględnia wpływ cech konstrukcyjnych kolektora i warunków jego eksploatacji. Określona na podstawie pomiarów energia promieniowania słonecznego i obliczona ilość ciepła użytecznego była podstawą do wyznaczenia efektywności badanych kolektorów w zależności od kata padania promieniowania słonecznego.

EN

The presented work includes the results of performed tests determining solar collector efficiency as a function of angle of incidence of solar radiation. Experimental tests were performed on a specially prepared test bench, enabling monitoring and archiving of critical parameters. Both the value of the available solar radiation flux and temperatures of heating medium at the input and output of the collector system and ambient temperature were analyzed. Useful heat from collectors was set out from Hottel-Whillier-Biliss equation, which takes into account impact of design features of the collector and its operating conditions. Energy of solar radiation determined based on measurements and calculated amount of useful heat served as a basis for setting out effectiveness of tested collectors depending on the angle of incidence of solar radiation.

5

Angle of incidence influence of abrasive particles on wear magnitude of hard facings metals

Jankura D.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2002

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z. 58 [193]

109-114

EN

The contribution presents the results of the research of resistance of hard facing metals in conditions of erosive wear. Two types of hard - surfacing electrodes with different chemical composition were used on creation of three layers hard facing metals. Chemical composition of electrodes determined difference in structure of surface deposit. We investigated the influence of angle of incidence of abrasive particles on wear magnitude of hard facing metals. The results of the experiments showed that intensity of wear is very depended on parameters of wear as well as structure morphology of hard facing metals.