Закон вязкости Ньютона

Закон вязкости (внутреннего трения) Ньютона — математическое выражение, связывающее касательное напряжение внутреннего трения $\tau$ (вязкость) и изменение скорости среды $v$ в пространстве $\partial v/\partial n$ (градиент скорости) для текучих тел (жидкостей и газов):

\tau =\eta {\frac {\partial v}{\partial n}},

где величина $\eta$ называется коэффициентом внутреннего трения или коэффициентом динамической вязкости (единица СИ - Па∙с, СГС — пуаз); с физической точки зрения она представляет собой удельную силу трения при градиенте скорости, равном единице.

В технике, в частности, при расчёте гидроприводов и в триботехнике, часто приходится иметь дело с величиной:

\nu ={\frac {\eta }{\rho }},

эта величина получила название кинематической вязкости (единица СИ - м²/с, СГС — Стокс). Здесь $\rho$ — плотность среды; $\eta$ — коэффициент динамической вязкости.

Закон Ньютона может быть получен аналитически и приёмами физической кинетики, где вязкость рассматривается обычно одновременно с теплопроводностью и соответствующим законом Фурье для теплопроводности. В кинетической теории газов коэффициент внутреннего трения вычисляется по формуле

\eta ={\frac {1}{3}}\left\langle u\right\rangle \left\langle \lambda \right\rangle \rho ,

где $\left\langle u\right\rangle$ — средняя скорость теплового движения молекул, $\left\langle \lambda \right\rangle$ − средняя длина свободного пробега.

См. также

Литература

Ю. И. Дытнерский. Процессы и аппараты химической технологии. Часть 1. Теоретические основы процессов химической технологии. — М.: Химия, 1995. — 400 с. — 6500 экз. — ISBN 5-7245-1006-5.

Read other articles:

My Beautiful Kingdom

Artikel ini sebatang kara, artinya tidak ada artikel lain yang memiliki pranala balik ke halaman ini.Bantulah menambah pranala ke artikel ini dari artikel yang berhubungan atau coba peralatan pencari pranala.Tag ini diberikan pada November 2022. My Beautiful KingdomSutradaraMak Wing-lunSkenarioXin YuanziTanggal rilis 13 Desember 2013 (2013-12-13) Durasi87 menitNegaraTiongkokBahasaMandarin My Beautiful Kingdom (Mandarin: 我的美丽王国) adalah film komedi romantis Tiongkok tahun 2013 ...

Lutetia

Peta Galia pada abad ke-1 SM, menunjukan lokasi Lutetia. Lutetia (kadang-kadang disebut Lutetia Parisiorum atau Lucotecia, dalam bahasa Prancis Lutèce) adalah kota di Galia pra-Romawi dan era Romawi. Orang Galia menetap di wilayah ini selama abad ke-3 SM. Nama Lutetia pertama kali dicatat oleh Julius Caesar dalam De Bello Gallico. Pranala luar Wikimedia Commons memiliki media mengenai Lutetia. Paris, a Roman city Arènes de Lutèce - Paris Parks & Gardens Artikel bertopik sejarah ini ada...

Grec

« GREC » redirige ici. Pour les autres significations, voir Grec (homonymie). Cet article est une ébauche concernant une langue et la Grèce. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Le grec (en grec moderne : Ελληνικά, romanisation : Elliniká) est une langue hellénique, seule survivante de cette famille. Sous sa forme moderne et démotique (νέα ελληνικά, δημ...

Barnes and Co. Trading Place

Historic site in Queensland, AustraliaBarnes and Co. Trading PlaceSmith & Miller Building (formerly Barnes & Co), 2015Location118 Palmerin Street, Warwick, Southern Downs Region, Queensland, AustraliaCoordinates28°13′03″S 152°01′58″E / 28.2176°S 152.0327°E / -28.2176; 152.0327Design period1900–1914 (early 20th century)Built1910–1911ArchitectWallace & Gibson Queensland Heritage RegisterOfficial nameBarnes and Co. Trading Place, Smith and Mil...

Polycythemia vera

Overproduction of red blood cells by the bone marrow Erythremia redirects here. For similar-sounding medical terms, see arrythmia and erythema. Medical conditionPolycythemia veraOther namesPolycythaemia vera (PV, PCV), erythremia, primary polycythemia, Vaquez disease, Osler-Vaquez disease, polycythemia rubra vera[1]Blood smear from a patient with polycythemia veraSpecialtyOncology, hematology In oncology, polycythemia vera (PV) is an uncommon myeloproliferative neoplasm in which the b...

Rudaki

Persian poet (858–940/41) For other uses, see Rudaki (disambiguation). RudakiStatue of Rudaki in Dushanbe, TajikistanBornc. 858Banoj, Samanid EmpireDied940/41 (aged 82 or 83)Banoj, Samanid EmpireOccupationPoetsingermusicianLanguageNew Persian Rudaki (also spelled Rodaki; Persian: رودکی; c. 858 – 940/41) was a poet, singer, and musician who is regarded as the first major poet to write in New Persian. A court poet under the Samanids, he reportedly composed more than 180,000...

Данио-рерио

Данио-рерио Научная классификация Домен:ЭукариотыЦарство:ЖивотныеПодцарство:ЭуметазоиБез ранга:Двусторонне-симметричныеБез ранга:ВторичноротыеТип:ХордовыеПодтип:ПозвоночныеИнфратип:ЧелюстноротыеГруппа:Костные рыбыКласс:Лучепёрые рыбыПодкласс:Новопёрые рыбыИн�...

约翰斯顿环礁

此條目可参照英語維基百科相應條目来扩充。 (2021年5月6日)若您熟悉来源语言和主题，请协助参考外语维基百科扩充条目。请勿直接提交机械翻译，也不要翻译不可靠、低品质内容。依版权协议，译文需在编辑摘要注明来源，或于讨论页顶部标记{{Translated page}}标签。约翰斯顿环礁Kalama Atoll 美國本土外小島嶼 Johnston Atoll 旗幟颂歌：《星條旗》The Star-Spangled Banner約翰斯頓環礁�...

Iowa Hawkeyes men's basketball

Men's basketball team of the University of Iowa Iowa Hawkeyes 2023–24 Iowa Hawkeyes men's basketball team UniversityUniversity of IowaAll-time record1,700–1,181–1 (.590)Head coachFran McCaffery (14th season)ConferenceBig TenLocationIowa City, IowaArenaCarver-Hawkeye Arena (Capacity: 15,400)Student sectionHawks NestColorsBlack and gold[1] Uniforms Home Away Alternate NCAA tournament runner-up1956NCAA tournament Final Four1955, 1956, 1980NCAA tournament ...

Flag of Prince George's County, Maryland

Prince George's CountyOther namesPrince Georgian flag, P.G. County flagUseOther Proportion3:5[1]Adopted1963; 61 years ago (1963)DesignA three-foot by five-foot white field, with a four inch-thick red cross atop it. In the canton is a rendition of the Prince George's County seal from 1958. The current flag of Prince George's County, Maryland, was adopted in 1963, replacing one that had been in use since 1696.[2] It is a 3 parts tall by 5 parts wide white field...

Mango cake

Filipino chiffon cake Mango roll redirects here. For the American-style makizushi, see Sushi § Western-style sushi. Mango cakeTop: Mango Passion cake from Red Ribbon Bakeshop;Bottom: Mango pianono (Mango rolls)Alternative namesMango cakeCourseDessertPlace of originPhilippinesSimilar dishesMango float, Crema de fruta Media: Mango cake Mango cake or mango chiffon cake, is a Filipino layered chiffon cake infused with ripe sweet Carabao mangoes. It is typically topped with mango c...

Ford Cosworth DFV

Cosworth DFVUn Ford Cosworth DFV di Formula 1Descrizione generaleCostruttoreCosworth Produzione1967–1983 Tipomotore a V di 90° Numero di cilindri8 Alimentazioneaspirato ad iniezione meccanica Lucas Schema impiantoCilindrata2993 cm³ Distribuzione4 valvole per cilindro, 4 alberi a camme in testa CombustioneCombustibilebenzina Raffreddamentoa liquido UscitaPotenzada 400 (1967) a circa 550 (1983) cavalli a seconda della versione PesoA vuoto163 kg PrestazioniUtilizzatoriÈ stato montato su mol...

Georgia Championship Wrestling

American professional wrestling promotion Georgia Championship WrestlingAcronymGCWFounded1944 2020 (revival)Defunct1984 (original promotion)StyleRasslin'HeadquartersAtlanta, GeorgiaFounder(s)Paul JonesOwner(s)Paul Jones (1944–1974)Jim Barnett (1974–1983)Jack Brisco (1983–1984)Jerry Brisco (1983–1984)Ole Anderson (1983–1984)Vince McMahon (1984)Grady Odom (1990–2020)Chris Nelms (2020–present)ParentGeorgia Championship Wrestling, Inc. (original promotion) Georgia Championship Wrest...

Albany Medical Center

Hospital in New York, United StatesAlbany Medical CenterAlbany Medical Center Pillars EntranceGeographyLocation43 New Scotland Avenue, Albany, New York, United StatesOrganizationFundingNon-profit hospitalTypeTeachingAffiliated universityAlbany Medical CollegeServicesEmergency departmentLevel I trauma centerBeds766HelipadIATA: NK64HistoryOpened1849LinksWebsitewww.albanymed.orgListsHospitals in New York State Albany Medical Center is the only academic medical center serving northeastern New Yor...

Hemphill County, Texas

County in Texas, United States Not to be confused with Hemphill, Texas. County in TexasHemphill CountyCountyHemphill County Courthouse in CanadianLocation within the U.S. state of TexasTexas's location within the U.S.Coordinates: 35°50′N 100°17′W / 35.83°N 100.28°W / 35.83; -100.28Country United StatesState TexasFounded1887Named forJohn HemphillSeatCanadianLargest cityCanadianArea • Total912 sq mi (2,360 km2) • L...

Vulcanization

Process of hardening rubber This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Vulcanization – news · newspapers · books · scholar · JSTOR (May 2023) (Learn how and when to remove this message) Worker placing a tire in a mold before vulcanization. Vulcanization (British English: Vulcanisation) is a range of pro...

Hüttenkopf (Allgäu Alps)

This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Hüttenkopf Allgäu Alps – news · newspapers · books · scholar · JSTOR (February 2016) (Learn how and when to remove this message) You can help expand this article with text translated from the corresponding article in German. (June 2010) Click [show] for important tra...

رباعي أضلاع لامبرت

رباعي أضلاع لامبرت في الهندسة، رباعي أضلاع لامبرت الذي يعرف أيضًا بـ رباعي أضلاع ابن الهيثم-لامبرت ،[1] الذي يحمل اسم العالمين ابن الهيثم ويوهان لامبرت، هو رباعي أضلاع يعد من الاستكشاف المبكرة المشهورة في الهندسة اللا إقليدية، والذي يتكون من قاعدة يتعامد عليه ضلعين، و�...

Why You Lose at Bridge

Book Why You Lose at Bridge AuthorS. J. SimonLanguageEnglishSubjectContract bridgePublished1945PublisherNicholson & WatsonPublication placeUnited KingdomPagesiv + 154OCLC18352804 Cut for Partners AuthorS. J. SimonLanguageEnglishSubjectContract bridgePublished1950PublisherNicholson & WatsonPublication placeUnited KingdomPagesiv + 128OCLC13548585 Why You Lose at Bridge is a book about the game of contract bridge by the Russian-born English bridge player S. J. Skid Simon (1904–48), fir...

首都圏トライアングル

この記事は検証可能な参考文献や出典が全く示されていないか、不十分です。出典を追加して記事の信頼性向上にご協力ください。（このテンプレートの使い方）出典検索?: 首都圏トライアングル – ニュース · 書籍 · スカラー · CiNii · J-STAGE · NDL · dlib.jp · ジャパンサーチ · TWL (2015年1月) 参加局のテレビ神奈川(tvk)本社屋首�...