Mvura, zvose zvinwiwa nemagasi, zvine mwero wakasiyana wekusimba. Kusimba kwesimba ndiko kusimba kwekukweshana pakati pemamorekuru anoumba mvura. Mamorekuru anoumba mvura inokweshana painoyerera. Mumvura, kusimba kwesimba kunokonzerwa nekubatana (kukwezvana pakati pemamorekuru akafanana). Mumagasi, kusimba kwesimba kunokonzerwa nekusangana kwemamorekuru.
Mvura inoyerera inowanzo yerera zviri nyore, semuenzaniso mvura. Kusiyana neizvi, mvura yakakora yakaoma kuyerera, semuenzaniso mafuta ekubikisa, mafuta, huchi, nezvimwewo. Unogona kuratidza izvi nekudurura mvura nemafuta ekubikisa pasi rakatsetseka. Mvura inoyerera nekukurumidza kupfuura mafuta ekubikisa kana mafuta. Kusimba kwemvura kunoenderanawo nekupisa. Kana tembiricha yemvura yakakwira, mvura yacho inotsvedza zvishoma. Semuenzaniso, kana amai vakagocha hove mukicheni, mafuta ekubikisa akakora pakutanga anova mvura yakawanda kana apiswa. Kusiyana neizvi, tembiricha yegesi yakakwira, ndipo panowedzera kutsvedza kwemhepo.
Kukwana kweViscosity
Kupenya kwemvura kunomiririrwa nechiratidzo η (verenga: eta). η = kupenya kwemvura. Saka mwero wekupenya kwemvura unoratidzwa ne kupenya kwemvura.
Rutivi rutete rwemvura runoiswa pakati pemaplate maviri. Kubatana isimba rinokwezva pakati pemamorekuru emhando imwe chete, ukuwo kunamira isimba rinokwezva pakati pemamorekuru emhando dzakasiyana. Simba rinonamira rinoshanda pakati peplate nerutivi rwemvura rwakabatana neplate (mamorekuru emvura nemamorekuru eplate zvinokwezvana). Simba rinobatana rinoshanda pakati pemaplate emvura (mamorekuru emvura anokwezvana).
Pakutanga, ndiro nechikamu chemvura zvinenge zvisina kumira (mufananidzo 1). Mushure meizvozvo, ndiro iri pamusoro inodhonzwa kurudyi (mufananidzo 2). Ndiro iri pasi haidhonzwe (ndiro iri pasi haina kumira). Hukuru hwesimba rekudhonzwa hunogadziriswa kuitira kuti ndiro iri pamusoro iende kurudyi nekukurumidza kusingachinji (v inogara ichichinjika). Nekuti pane simba rinonamira rinoshanda pakati pemucheto wendiro nechikamu chemvura yakabatana nendiro, mvura iri pasi pendiro inochinjawo kurudyi. Nekuti pane simba rakabatana pakati pemamorekuru emvura, mvura yakachinjika kurudyi yakakwezva mvura iri pasi.
Chikamu chemvura chiri pamusoro chinodhonza mvura iri pasi kuti iende kurudyi, zvakasiyana chikamu chemvura chiri pasi chinobata mvura iri pamusoro, saka kumhanya kwemvura kunosiyana. Chikamu chemvura chiri pamusoro chinofamba nekumhanya kukuru (v), mvura iri pasi inofamba pa v diki, zvichingodaro. Saka kana v yakaderera, idiki. Nemamwe mashoko, kumhanya kwechikamu chemvura kunochinja nguva nenguva kubva kumusoro kuenda pasi kusvika pa l.
Kuchinja kwe fluid layer velocity (v) kwakakamurwa nedaro rinoitika shanduko (l) = v/l. V/l inozivikanwa se velocity gradient. Plate iri pamusoro inogona kufamba nekuda kwe tensile force (F). Kune imwe fluid, hukuru hwe tensile force inodiwa hunoenderana zvakananga nenzvimbo ye fluid yakabatana neplate (A), fluid speed (v) uye inversely proportional to the distance l. Pamasvomhu, inogona kunyorwa seinotevera:
Fomura ye viscosity coefficient
Kare, zvakatsanangurwa kuti mvura dzakatetepa dzinowanzo yerera zviri nyore, nepo mvura dzakakora dzichiomera kuyerera. Kuyerera kwemvura kunoratidzwa ne viscosity coefficient yayo. Kana mvura yacho yakakora, simba rekudhonza rinodiwa rakakura. Muchiitiko ichi, simba rekudhonza rinoenderana zvakananga ne viscosity coefficient. Pamasvomhu, izvi zvinogona kunyorwa seizvi:
Information :
η = Kukosha kwekusimba
F = Simba
l = Kureba
A = Nzvimbo yepamusoro
v = Kumhanya
∝ = zvakaenzana
Sangano reInternational System of Units (SI) re viscosity coefficient iNs/m 2 = Pa.s (pascal second). CGS unit (centimeter gram second) ye viscosity coefficient idyn.s/cm 2 = poise (P). Viscosity inowanzo ratidzwa mu centipoise (cP). 1 cP = 1/100 P. Poise unit inoshandiswa kurangarira musayendisiti wekuFrance, mushakabvu Jean Louis Marie Poiseuille (anonzi: pwa-zoo-yuh).
1 poise = 1 dyn . s/cm 2 = 10 -1 Ns/m 2
