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Tytuł:
Basic flows of generalized second grade fluids based on a Sisko model
Autorzy:
Walicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/264558.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Sisko fluids
similar fluids
simple flows
przepływ płynu lepkiego
lepkoplastyczność
przepływ Poiseuille'a
Opis:
The present investigation is concerned with basic flows of generalized second grade fluids based on a Sisko fluid. After formulation of the general equations of motion three simple flows of viscoplastic fluids of a Sisko type or fluids similar to them are considered. These flows are: Poiseuille flow in a plane channel, Poiseuille flow in a circular pipe and rotating Couette flow between two coaxial cylinders. After presentation the Sisko model one was presented some models of fluids similar to this model. Next it was given the solutions of equations of motion for three flows mentioned above.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 1019-1033
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple flows of pseudoplastic fluids based on DeHaven model
Autorzy:
Walicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/266230.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
DeHaven fluids
similar fluids
simple flows
płyn lepkosprężysty
reologia
łożysko
Opis:
In this paper three simple flows of visco-plastic fluids of DeHaven type or fluids similar to them are considered. These flows are: Poiseuille flow in a plane channel, Poiseuille flow through a circular pipe and rotating Couette flow between two coaxial cylinders. After presentation DeHaven model it was presented some models of fluids similar to this model. Next it was given the solutions of equations of motion for three flows mentioned above.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 1035-1044
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flows of Newtonian and power-law fluids in symmetrically corrugated cappilary fissures and tubes
Autorzy:
Walicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/266107.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyn energetyczny
przepływ laminarny
rurka kapilarna
power-law fluid
laminar flow
symmetrically corrugated capillaries
capillary fissures
capillary tubes
Opis:
In this paper, an analytical method for deriving the relationships between the pressure drop and the volumetric flow rate in laminar flow regimes of Newtonian and power-law fluids through symmetrically corrugated capillary fissures and tubes is presented. This method, which is general with regard to fluid and capillary shape, can also be used as a foundation for different fluids, fissures and tubes. It can also be a good base for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. Five converging-diverging or diverging-converging geometrics, viz. wedge and cone, parabolic, hyperbolic, hyperbolic cosine and cosine curve, are used as examples to illustrate the application of this method. For the wedge and cone geometry the present results for the power-law fluid were compared with the results obtained by another method; this comparison indicates a good compatibility between both the results.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 1; 187-211
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of the flow through porous layers composed of converging-diverging capillary fissures or tubes
Autorzy:
Walicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/266040.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ laminarny
warstwa porowata
rurki kapilarne
laminar flow
symmetrically corrugated capillaries
capillary fissures
capillary tubes
porous layer
Opis:
In this paper, a porous medium is modelled by a network of converging-diverging capillaries which may be considered as fissures or tubes. This model makes it necessary to consider flows through capillary fissures or tubes. Therefore an analytical method for deriving the relationships between pressure drops, volumetric flow rates and velocities for the following fluids: Newtonian, polar, power-law, pseudoplastic (DeHaven and Sisko types) and Shulmanian, was developed. Next, considerations on the models of pore network for Newtonian and non-Newtonian fluids were presented. The models, similar to the schemes of central finite differences may provide a good basis for transforming the governing equations of a flow through the porous medium into a set of linear or quasi-linear algebraic equations. It was shown that the some coefficients in these algebraic equations depend on the kind of the capillary convergence.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 1; 161-185
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical parameters of the curvilinear squeeze film bearing lubricated by a Gecim-Winer fluid
Autorzy:
Walicka, A.
Walicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/265583.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
modified Reynolds equation
squeeze film
mechanical parameters of bearing
additives
równanie Reynoldsa
łożysko ślizgowe
równanie ruchu
Opis:
Based upon a Gecim-Winer fluid flow model, a curvilinear squeeze film bearing is considered. The equations of motion are given in a specific coordinates system. After general considerations on the Gecim-Winer fluid flow these equations are used to derive the Reynolds equation. The solution of this equation is obtained by a method of successive approximation. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of the Gecim-Winer fluid flow in gaps of two simple bearings: radial and spherical are presented.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 2; 465-473
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thrust porous bearing with rough surfaces lubricated by a rotem-shinnar fluid
Autorzy:
Walicka, A.
Walicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/387536.pdf
Data publikacji:
2016
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
pseudo-plastic fluid
rotem-shinnar model
thrust bearing
porous layer
Christensen roughness
płyn pseudoplastyczny
łożysko oporowe
warstwa porowata
teoria Christensena
model Rotem-Shinnar
Opis:
In the paper the influence of both bearing surfaces roughness and porosity of one bearing surface on the pressure distribution and load-carrying capacity of a thrust bearing surfaces is discussed. The equations of motion of a pseudo-plastic fluid of Rotem-Shinnar, are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation and Christensen theory of hydrodynamic lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for the cases of squeeze film bearing and externally pressurized bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing with squeezed film is considered as a numerical example.
Źródło:
Acta Mechanica et Automatica; 2016, 10, 1; 50-55
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorytm dekompozycji i modelowania sygnału full-waveform w lotniczym skaningu laserowym
An algorithm for full-waveform laser scanning signal decomposition and modeling
Autorzy:
Walicka, A.
Borkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/341293.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Przyrodniczy we Wrocławiu
Tematy:
lotniczy skaning laserowy
full waveform
aproksymacja
dekompozycja sygnału
airborne laser scanning
approximation
signal decomposition
Opis:
Lotniczy skaning laserowy jest obecnie jedną z najwydajniejszych technik pozyskiwania danych o powierzchni i elementach pokrycia terenu. Dynamiczny rozwój technologii pozwolił na szersze zastosowanie systemów typu full-waveform, które rejestrują kształt całej krzywej fali powracającej do odbiornika. W celu pozyskania dodatkowych informacji o obiektach, od których nastąpiło odbicie, zapisane dyskretne wartości przybliża się za pomocą zestawu funkcji parametrycznych. Prace badawcze koncentrują się na tworzeniu algorytmów pozwalających na przeprowadzenie szybkiej dekompozycji fali przy jednoczesnym wykryciu i aproksymacji słabych oraz nakładających się ech. Większość istniejących metod dekompozycji wymaga znajomości liczby wierzchołków występujących w sygnale i określenia przybliżonych parametrów wpasowywanych krzywych. W artykule zaproponowano alternatywny algorytm będący modyfikacją metody progresywnej, który pozwala na skuteczne przeprowadzenie dekompozycji sygnału z pominięciem prac przygotowawczych. Metoda polega na iteracyjnym wpasowaniu krzywych za pomocą algorytmu Levenberga–Marquardta z zastosowaniem wagowania poszczególnych sampli. Wykorzystując dane testowe, wykonano dwuetapową walidację algorytmu. W pierwszej kolejności zbadano wielkość i rozkład błędów aproksymacji powstałych podczas dekompozycji sygnału przy zastosowaniu funkcji Gaussa. W drugim etapie porównano otrzymane wyniki z wynikami aproksymacji za pomocą standardowej procedury. Na podstawie walidacji algorytmu można stwierdzić, że umożliwia on prawidłowe wykrycie wszystkich komponentów oraz ich poprawną aproksymację przy użyciu wybranego modelu matematycznego.
Airborne laser scanning is one of the most powerful techniques for acquiring information about Earth’s surface and land cover. Dynamic development of technology enabled the broader use of full-waveform’s type systems, which register the entire reflected waveform. In order to provide some additional information about the structure of the illuminated surface, discrete values should be approximated by parametric functions. Research is focused on algorithm development that would allow to carry out a rapid decomposition of the wave while detecting and approximating weak and overlapping echoes. Most of existing methods for full-waveform signal modeling requires knowledge of the number of peaks and approximate parameter values. In this paper new algorithm for signal decomposition has been investigated. It allows to carry out the decomposition effectively without preprocessing. This algorithm can be considered as a progressive algorithm modification. The method involves an iterative curve fitting using weighted Levenberg-Marquardt algorithm. Two-step validation of decomposition method has also been carried out on test data. Firstly, the quantity and distribution of approximation error have been investigated. Furthermore the results have been compared to standard procedure. Basing on algorithm validation it can be stated that the method allows proper detection of all components and their correct approximation.
Źródło:
Acta Scientiarum Polonorum. Geodesia et Descriptio Terrarum; 2016, 15, 1-4; 35-48
1644-0668
Pojawia się w:
Acta Scientiarum Polonorum. Geodesia et Descriptio Terrarum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pressure distribution in a porous squeeze film bearing lubricated with a Herschel-Bulkley fluid
Autorzy:
Walicka, A.
Jurczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/265480.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
smar
łożyska
plastyczność
thrust bearing
squeeze film
porous bearing
Herschel-Bulkley lubricant
Opis:
The influence of a wall porosity on the pressure distribution in a curvilinear squeeze film bearing lubricated with a lubricant being a viscoplastic fluid of a Herschel-Bulkley type is considered. After general considerations on the flow of the viscoplastic fluid (lubricant) in a bearing clearance and in a porous layer the modified Reynolds equation for the curvilinear squeeze film bearing with a Herschel-Bulkley lubricant is given. The solution of this equation is obtained by a method of successive approximation. As a result one obtains a formula expressing the pressure distribution. The example of squeeze films in a step bearing (modeled by two parallel disks) is discussed in detail.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 951-965
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reynolds number effects in the flow of a Vočadlo electrorheological fluid in a curved gap
Autorzy:
Walicka, A.
Falicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/264673.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
inertia effects
fixed surfaces of revolution
Vočadlo ER fluid
pressurized flow
bezwładność
przepływ ciśnieniowy
powierzchnia obrotowa
Opis:
Many electrorheological fluids (ERFs) as fluids with micro-structure demonstrate a non-Newtonian behaviour. Rheometric measurements indicate that some flows of these fluids may by modelled as the flows of a Vočadlo ER fluid. In this paper, the flow of a Vočadlo fluid – with a fractional index of non-linearity – in a narrow gap between two fixed surfaces of revolution with a common axis of symmetry is considered. The flow is externally pressurized and it is considered with inertia effect. In order to solve this problem the boundary layer equations are used. The Reynolds number effects (the effects of inertia forces) on the pressure distribution are examined by using the method of averaged inertia terms of the momentum equation. Numerical examples of externally pressurized flows in the gap between parallel disks and concentric spherical surfaces are presented.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 675-695
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of total inertia effects in a thrust curvilinear bearing lubricated with Newtonian lubricants
Autorzy:
Walicka, A.
Jurczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/265900.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
inertia
modified Reynolds equation
pressure distribution
load-capacity
bezwładność
równanie Reynoldsa
rozkład ciśnienia
nośność
Opis:
In the paper, the flow of a Newtonian type of lubricant in the clearance of a curvilinear bearing is considered. It is assumed that the bearing walls are modelled as smooth and impermeable. In analytical considerations, full inertia of the longitudinal flow and partial inertia of the circumferential flow are taken into account. The equation of motion of the lubricant is solved by the modified method of averaged inertia. A thrust bearing and spherical bearing are considered, for which dimensionless pressure distributions and the bearing capacity are given.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 1045-1058
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical parameters of the squeeze film curvilinear bearing lubricated with a Prandtl fluid
Autorzy:
Walicka, A.
Walicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/265737.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
równanie Reynoldsa
płyn Prandtla
parametry mechaniczne
łożysko
additives
mechanical parameters of bearing
squeeze film
Prandtl fluid
modified Reynolds equation
Opis:
Based upon a Prandtl fluid flow model, a curvilinear squeeze film bearing is considered. The equations of motion are given in a specific coordinate system. After general considerations on the Prandtl fluid flow these equations are used to derive the Reynolds equation. The solution of this equation is obtained by a method of successive approximation. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of the Prandtl fluid flow in gaps of two simple bearings are presented.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 967-978
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Drug diffusion transport through human skin
Autorzy:
Walicka, A.
Iwanowska-Chomiak, B.
Powiązania:
https://bibliotekanauki.pl/articles/265397.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
ludzka skóra
dyfuzja
dostarczanie leków
drug delivery
human skin
diffusion
Opis:
The stratum corneum (SC) forms the outermost layer of the human skin and is essentially a multilamellar lipid milieu punctuated by protein-filled corneocytes that augment membrane integrity and significantly increase membrane tortuosity. The lipophilic character of the SC, coupled with its intrinsic tortuosity, ensure that it almost always provides the principal barrier to the entry of drug molecules into the organism. Drugs can be administered either as suspensions or as solutions and the formulation can range in complexity from a gel or and ointment to a multilayer transdermal path. In this paper, we discuss theoretical principles used to describe transdermal release and we show that relatively simple membrane transport models based on the appropriate solution to the Fick’s second law of diffusion can be used to explain drug release kinetics into such a complex biological membrane as the human skin. To apply the Fick’s law we introduced into our considerations a brick-and-mortar model with two factors of tortuosity. Assuming that the mortar thickness is variable we also introduced the hindrance factor allowing us to model this variability. Having the modified Fick’s equation we presented its general solution and two special cases of this solution frequently applicable in permeation experiments. It seems that the solutions presented herein better approximate the real conditions of drug delivery then these well known.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 4; 977-988
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractal model of transdermal drug delivery
Autorzy:
Walicka, A.
Iwanowska-Chomiak, B.
Powiązania:
https://bibliotekanauki.pl/articles/264824.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
dostarczanie leków
ludzka skóra
naskórek
model fraktalny
drug delivery
human skin
epidermis
fractal model
Opis:
Skin, separating the vital organs of a human body, is a desirable route for drug delivery. However, the intact skin is normally permeable only for drug molecules with a low molecular weight. The stratum corneum (SC), being the outermost layer of the skin and the epidermis being the second – more permeable – layer of the skin, play an essential function in transdermal drug delivery. Physical and chemical methods of skin poration are used to enhance transdermal drug delivery. Each poration leads to an irregular system of pores which are connected with a system of micro-capillaries passing through the epidermis. Both the systems by their irregularity form a fractal porous matrix. Drugs administrated by this matrix can be either suspensions and solutions or creams and gels, therefore they have to be modelled as non-Newtonian fluids. To analyse the fluid flow through the porous matrix the model of the epidermis is assumed as gobbet-andmortar with the tortuous mortar of variable thickness and after transition from the mortar to the tube one considered classical and fractal capillary flows of selected non-Newtonian fluids. Fractal expressions for the flow rate, velocity and permeability of fluids flow in a porous matrix are derived based on the fractal properties of the epidermis and capillary model. Each parameter in the proposed expressions does not contain any empirical constant and has a clear physical meaning and the proposed fractal models relate the flow properties of considered fluids with the structural parameters of the epidermis as a porous medium. The presented analytical expressions will help understand some of the physical principles of transdermal drug delivery.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 4; 989-1004
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mass transport through interstitial structures
Autorzy:
Iwanowska-Chomiak, B.
Walicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/265600.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
modele fraktalne
płyn śródmiąższowy
śródmiąższe
interstitial space
interstitial fluid
fractal models
Opis:
Interstitial space, also called interstitum, separating the vital organs of a human body, is the primary source of lymph and is a major fluid compartment in the body. Interstitial space (IS) is filled out by thick collagen (CL) bundles which form lattices represented by a network of capillaries. This network has the structure similar to a sponge porous matrix (SPM) with pores-capillaries of variable cross-section. To analyse the mass transport of interstitial fluids (IFs) through the porous matrix it is assumed that the SPM is composed of an irregular system of pores which may be modelled as a fractal porous matrix. The interstitial fluids can be either bio-suspensions or bio-solutions and therefore they have to be modelled as non-Newtonian fluids. Analysing the fluid flow through the porous matrix it is assumed that the SPM is modelled as capillary tubes of variable radii. Introducing a hindrance factor allowed us to consider the porous matrix as a system of fractal capillaries but of constant radii. Classical and fractal expressions for the flow rate, velocity and permeability are derived based on the physical properties of the capillary model of interstitial structures. Each parameter in the proposed expressions does not contain any empirical constant and has a clear physical meaning, and the proposed fractals models relate the flow properties of the fluids under consideration with the structural parameters of interstitium as a porous medium.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 66-91
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inertia effects in a multilobe conical bearing lubricated with a couple stress fluid
Autorzy:
Walicka, A.
Walicki, E.
Jurczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/265020.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
efekt bezwładności
równanie Reynoldsa
metoda Galerkina
łożysko
inertia effects
modified Reynolds equation
Galerkin method
mechanical parameters of bearing
additives
Opis:
In this paper, a multilobe conical bearing is analyzed. A lubricant modelled by a couple stress fluid flows In the bearing clearance . The Galerkin method is used to determine the mechanical parameters of multilobe journal bearings. An example of a two-lobe conical bearing is discussed in detail. The inertia of the flowing lubricant is taken into account in the analysis. It has been found that the increase of the couple stress generates an increase the pressure in the clearance.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 439-451
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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