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The basic closures of fluid mechanics in form characteristic for the Finite Volume Method

100%

Sobieski W.

Technical Sciences / University of Warmia and Mazury in Olsztyn

2013

tom nr 16(2)

93--107

This short article presents all basic “closures” that are needed to supplementation the general set of balance equations in form characteristic for the Finite Volume Method. In subsequent chapters the equation of state, viscous molecular stress tensor, turbulent stress tensor, molecular heat flux, turbulent heat flux and momentum and energy sources were described. This article is a second part of a cycle dedicated for the mathematical basis of Finite Volume Method. The motivation for writing the article follows from the observation that the Finite Volume Method is usually described in greater detail in monographic books, or very briefly in the basic books dedicated to fluid mechanics. This article is an attempt to center justifications of these approaches, so that in the simplest way show the readers the basic knowledge of the so-called Computational Fluid Mechanics. For this reason this article can be treated as a literature review.

Numerical modeling of environmental flows using DAM: Some preliminary results

100%

Walters R. A. , Plew D. R.

Acta Geophysica

2008

tom Vol. 56, no. 3

918-934

Development of closures and parameterizations for subgrid scale effects is a significant and longstanding problem in the numerical simulation of environmental flows. The model described herein uses a rigorous approach for developing double-averaged governing equations — first a traditional Reynolds averaging to derive the Reynolds averaged Navier-Stokes equation (RANS), then a volume average to derive a set of double-averaged equations (DANS). An existing finite element flow model is then modified to accommodate these equations. This process gives rise to several new terms that require closures, as well as a new equation for free surface elevation. This paper is directed toward model development and uses several existing closure schemes as test cases.

Distinguishability Operations and Closures

75%

Câmpeanu C. , Moreira N. , Reis R.

Fundamenta Informaticae

2016

tom Vol. 148, nr 3/4

243--266

Given a language L, we study the language of words D(L), that distinguish between pairs of different left quotients of L. We characterize this distinguishability operation, show that its iteration has always a fixed point, and we generalize this result to operations derived from closure operators and Boolean operators. For the case of regular languages, we give an upper bound for the state complexity of the distinguishability operation, and prove its tightness. We show that the set of minimal words that can be used to distinguish between different left quotients of a regular language L has at most n - 1 elements, where n is the state complexity of L, and we also study the properties of its iteration. We generalize the results for the languages of words that distinguish between pairs of different right quotients and two-sided quotients of a language L.

Badania wytrzymałościowe blach aluminiowych stosowanych w przemyśle spożywczym

63%

Sulewski L. , Kowalski M. , Wernik J.

Przemysł Chemiczny

2024

tom T. 103, nr 12

1483--1486

Przedstawiono zagadnienie badawcze dotyczące minimalizacji zużycia stopu aluminiowego do produkcji zakrętek opakowań szklanych, co ma istotny wpływ na odpowiedni dobór parametrów procesu technologicznego. Do produkcji zakrętek opakowań szklanych stosowane są najczęściej blachy z normowanego stopu aluminium EN AW-8011A, który cechuje się bardzo dobrą formowalnością. Stop jest szeroko stosowany w przemyśle, m.in. do produkcji wymienników ciepła. Literatura przedmiotu wskazuje, że nadal istnieje zapotrzebowanie na stopy aluminiowe o większej wytrzymałości i ciągliwości. Wykonano badania wytrzymałościowe nowego stopu aluminium 5801 i porównano go z właściwościami stopu AW-8011A. Uzyskane wyniki wskazują, że aluminium serii 5801 jest lepszym materiałem do produkcji elementów metodą tłoczenia blachy.

Samples of 0.18 and 0.19 mm thick sheets of 5801 Al alloy and 0.2 mm thick sheets of AW-8011A alloy were analyzed for tensile strength, yield strength, modulus of elasticity, and elongation at break. The effects of material thickness and heat-technol. treatment, including painting and one- or two-sided hardening of the paint, were studied. The Lankford coeff. and the planar and normal anisotropy index were detd. based on recording geometric changes of the sample during the tensile process. Samples made of heat-treated 5801 sheet were stronger compared to the corresponding ones made of 8011A sheet.