Mvura, zvinhu zvemvura negasi zvemhando dzakasiyana, zvine mwero wakasiyana wekupenya. Kupenya kupopotedzana pakati pemamorekuru anoumba mvura. Saka, mamorekuru anogadzira kupopotedzana kwemvura kana mvura yayerera. Muzvinwiwa, kupenya kunokonzerwa nemasimba ekubatana (anodhonza masimba pakati pemamorekuru akafanana). Asi muzvinhu zvegasi, kupenya kunokonzerwa nekusangana pakati pemamorekuru.
Mvura inoyerera iri nyore kuyerera, semuenzaniso, mvura. Kusiyana neizvi, mvura yakakora yakaoma kuyerera, semuenzaniso, mafuta anozorwa. Unogona kuratidza nekudurura mvura nemafuta panzvimbo yakakombama. Mvura inoyerera nekukurumidza kupfuura mafuta. Huremu hwemvura inoyererawo zvinoenderana nekupisa. Kana tembiricha yemvura yakakwira, mvura inotsvedza zvishoma. Semuenzaniso, kana amai vakakangwa hove mukicheni, mafuta ekubikisa ayo anotanga kukora anova mvura yakawanda kana apiswa. Kusiyana neizvi, tembiricha yechinhu chegasi yakakwira, ndipo panonyanya kukobvu mafuta egasi.
Kuenzana kweViscosity
Chiratidzo η chinomiririra viscosity yemvura (verenga: eta). η = coefficient of viscosity. Saka, huwandu hwe viscosity yemvura hunoratidzwa ne viscosity coefficient yemvura.
Rutivi rutete rwemvura runoiswa pakati pemaplate maviri. Kubatana isimba rinokwezva pakati pemamorekuru akafanana, nepo kunamira isimba rinokwezva pakati pemamorekuru akasiyana. Masimba ekunamatira anoshanda pakati peplate nerutivi rwemvura rwakabatana neplate (mamorekuru emvura nemamorekuru eplate anokwezvana). Panguva imwe chete, masimba ekubatana anoshanda pakati pemamembrane emvura (mvura inokwezvana).
Pakutanga, ndiro nerukoko rwemvura zvinenge zvamira (mufananidzo 1). Mushure mezvo, ndiro iri pamusoro inodhonzwa kurudyi (mufananidzo 2). Mahwendefa ari pasi haadhonzwe (ndiro iri pasi inenge yamira). Hukuru hwesimba rekudhonza hwakarongwa zvekuti ndiro iri pamusoro inochinja kuenda kurudyi nekumhanya kwakasimba (v constant). Nekuti pane simba rekunamatira rinoshanda pakati pemucheto wendiro nechikamu chemvura yakabatana nendiro, mvura iri pasi pendiro inochinjawo kuenda kurudyi. Nekuti pane simba rakabatana pakati pemamorekuru emvura, mvura inofamba ichienda kurudyi inodhonza mvura iri pasi.
Chikamu chemvura chiri pamusoro chinodhonza mvura iri pasi kuti iende kurudyi,
nepo chikamu chemvura chiri pasi chichibata mvura iri pamusoro, saka mwero wemvura unosiyana. Chikamu chemvura chiri pamusoro chinofamba ne (v) rate yakakura, mvura iri pasi inofamba ne v diki, zvichingodaro. Saka, pasi pasi v, diki. Nemamwe mashoko, kumhanya kwechikamu chemvura kunochinja nguva nenguva kubva kumusoro kuenda pasi kusvika pa l.
Kuchinja kwespeed ye fluid layer (v) kwakakamurwa nedaro re change (l) = v / l. V/l inozivikanwa se speed gradient. Maplate ari pamusoro anogona kufamba nekuti pane simba rekudhonza (F). Kune mamwe ma fluids, huwandu hwekukwezva hunodiwa hwakanangana nenzvimbo ye fluid yakabatana ne plate (A), chiyero che fluid (v) uye inversely proportional nedaro l. Pamasvomhu, inogona kunyorwa seinotevera:
Kare, zvakatsanangurwa kuti mvura yakatetepa inowanzova nyore kuyerera, nepo mvura yakakora ichiva yakaoma kuyerera. Kuenzana kwekunaka kunoratidza huwandu hwekunaka kwemvura. Kana mvura yacho yakakora, simba rekunamira rinodiwa rakakurawo. Muchiitiko ichi, simba rekunamira rinoenderana zvakananga nechiyero chekunaka. Pamasvomhu zvinogona kunyorwa seizvi:
η = coefficient ye viscosity, F = simba, l = daro, A = nzvimbo yepamusoro, v = kumhanya, ∝ = kuenzanisa
Chikwata cheInternational System Unit (SI) che coefficient of viscosity iNs/m2 = Pa.s (pascal second). CGS unit (masendimita gram second) ye coefficient viscosity idyn.s/cm2 = poise (P). Viscosity inowanzo ratidzwa mu centipoise (cP). 1 cP = 1/100 P. Chiyero che poise chinoshandiswa mukukudza musayendisiti wekuFrance, Jean Louis Marie Poiseuille (verenga: pwa-zoo-yuh).
1 poise = 1 dyn. s/cm2 = 10-1 Ns/m2
