Von Karman vortices

Turbulence haisipo chete mumasikirwo, zvisinei iwe unotarisa pairi, asi inonyanya kukosha mumamiriro ezvinhu akawanda: kusanganisa zviri nani zvinwiwa zvakasiyana (ndicho chikonzero isu tinozunza kofi nemukaka kuti tivasanganise), kana kugadzira kuchinjisa kukuru kwekupisa pakati. zvinwiwa (isu zvakare tinozunza kofi kuti iite kutonhora nekukurumidza), nezvimwe. Muchidzidzo chemamiriro ekunze varikowo uye vanonzi Von Karman vortices.

Muchinyorwa chino, tichatsanangura zvese zvaunoda kuziva nezveVon Karman marori ekurasa, maitiro awo, uye kukosha kwawo.

Von Karma vortex properties

Kutanga, tinofanira kuziva zvimiro zvinotsanangura mvura uye masimba ayo. Density, pressure kana tembiricha zvinhu zvatisinga zive tose. Zvichibva pazviri uye nemhedzisiro yavo, chero kufamba kana simba remvura rinogona kutsanangurwa, zvisinei nekuti zvingave zvakaoma sei:

Kugadzikana

Fungidzira kuyerera kwemhepo ichirova bhora; kana mhepo inomhanya yakaderera, tinoona kuti mhepo inofamba "zvinyoro" kumativi ose uye shure kwebhora; musana uyu unonziwo "kudzika" kana "muswe" wekuyerera kwemvura.

Muchiitiko ichi, kuyerera kunonzi laminar, ndiko kuti: hapana eddies kana kuti inowanzonzi mhirizhonga inoonekwa, chokwadi ndechokuti pasina mhirizhonga zvinhu zvose zvingave zvinofinha; Kutaura zvazviri, kunyange Navier-Stokes equations inogona kuva nekushandiswa mune zvepfungwa, kutonga kwevanhu vakawanda, kana kugadzirwa kwevanofamba netsoka evacuation systems munhandare, nezvimwewo. Zvose zviri nyore kana pasina mhirizhonga.

Zvino fungidzira kuti molekuru imwe neimwe yemhepo inotevera imwe molecule yemhepo, zvichingodaro; kune nhamba isingaperi yemamorekuru pamwe chete nemutsetse wakatsetseka. Ngatimbofungidzira kuti, chero "chikonzero", pane kamwe kamwe molecule isingateveri iyi ine simba patani, ndiko kuti, inosiya "yakajairika" trajectory, kunyangwe kashoma; technically kutaura, zvinonzi zvinoitika "zvisina kugadzikana". Kusagadzikana uku ndiko kutanga kwemhirizhonga; Kubva panguva iyoyo zvichienda mberi, shanduko dzematrajectories dzinotevera zvine musoro, sezvo imwe morekuru inosundidzira imwe kuti ichinje nzira, zvichingodaro. "chikonzero" nei pakutanga.

Molecular trajectories inogona kunge yakanyanya, yakasiyana-siyana: yakanyatsojeka shanduko yekushisa, kumanikidza kana kuwanda, kunyangwe iwo akajairika asingazivikanwe kwaakabva.

Zvichienderana nejometri kana chimiro chinoumba chinotevera, kusagadzikana kunogamuchira mazita anotevera:

Kelvin-Helmholtz kusagadzikana: Inogona kuitika mukuyerera mukati memvura inoenderera semhepo kana mvura, kana pakusangana kwemvura mbiri kana maviri akaturikidzana emvura yakafanana inofamba nekumhanya kwakasiyana.
Rayleigh-Taylor kusagadzikana: Zvakakosha mu "kuwa" (kuputsika) kana kuburuka kwemhepo inotonhora kubva kumusoro. Kunyangwe mu "kupinza" kukwira kwemhepo inopisa.

Viscosity

Viscosity ingangove inozivikanwa nekuti munhu wese anofananidza mvura nehuchi kana lava, semuenzaniso, kufungidzira kuti viscosity chii. Ngatimbofungidzirai nerimwe divi: Ngatitii tiri parobhoti rine motokari dziri mberi neshure; kana robhoti raita girinhi, tinoda nguva yekufamba; zvino: viscosity yakafanana nekuita nguva pakati peumwe neumwe anotakura anotakura (1 / kuita nguva); iyo yakakwirira viscosity, iyo ipfupi yekuita nguva; kureva kuti, zvinwiwa zvose zvinowanzofamba pamwe chete kana pamwe chete.

Viscosity inowanzofungidzirwa sesimba rinopokana pakati pemamorekuru ari mumvura. Iyo yakakwirira friction, iyo yakakwirira viscosity. Pakati pezvimwe zvinhu, simba iri ndiro chikonzero chekuvapo kwemuganhu wemuganhu: iyo iri pedyo nemhepo iri pamusoro, iyo yakaderera kukurumidza kwayo (mumufananidzo uri pasi apa, museve mupfupi unoratidza kukurumidza kunonoka).

Somuenzaniso, maparaglider uye kunyange vatyairi vendege vanoziva kuti kana mhepo ichivhuvhuta (nengozi) yakasimba, vanogona kuburuka, nokuti “kukweshwa” nemiti kunoderedza simba ravo zvikuru.

Kuenderera mberi nemuenzaniso webhora watakambotaura, semuenzaniso, kana kuyerera kwemhepo pamusoro pebapiro kwakanyatso laminar uye pasina muganhu wepamusoro (iyo yatinotoziva yakangofanana nekutaura hakuna viscosity), hapana mutsauko.kumanikidza pakati pepamusoro. uye pasi pebapiro, saka hapana kusimudza; ndege haigoni kubhururuka; zviri nyore. Kubhururuka hakubviri zvachose, asi rombo rakanaka kuti kunamatira kunogara kuripo. Uyezve, pasina viscosity, havangakonzeri mhirizhonga pasinei nekusagadzikana.

Kuunganidzwa kwenyaya nekudzikira

Kana chimedu (chakadai semhepo molecule) chiri pamhepo yakaderera, chinochikweva nekukasira kunopiwa neshanduko yedzvinyiriro yakakamurwa nedensity. Nekudzvinyirirwa kwepamusoro izvo zvinopesana zvinoitika, zvinodzinga kana kusunda.

Mune mamiriro ekunze, nzvimbo dzekumanikidza kwakanyanya dzinonzi anticyclones, nepo madutu kana madutu (extratropical cyclones chete muzviitiko zvakakosha) Vanonzi low pressure zones.. Mhepo yese iri mumhepo kana mvura yese iri mumakungwa ePanyika inofamba nekuda kwekusiyana kwematsimba aya. Dzvinyiriro ndiamai vezvinhu zvose; Kutaura zvazviri, mamwe akawanda akasiyana-siyana anokanganisa kuchinja kwekumanikidzika: density, tembiricha, viscosity, giravhiti, masimba eCoriolis, inertias dzakasiyana-siyana, nezvimwewo; Kutaura zvazviri, kana molecule remhepo richifamba, rinodaro nokuti molecule rinotangira rasiya nharaunda ine simba rakaderera, dunhu rinowanzozadza pakarepo.

Takaona zvikonzero kana kusagadzikana kunomuka munhau semhepo kana gungwa, zvichigadzira mamwe majeometri, imwe yacho - musoro webasa iri - ndiwo anonzi Von Karman vortices. Zvino, kana tangonzwisisa zvinokonzeresa uye zvinochinjika zvinokanganisa masimba echero mvura, tagadzirira kudzidza nezve iyi chaiyo geometry.

Kana mafambiro emhepo achitenderera chero geometry, inoshanduka ichiipoteredza, zvichiita kuti pave nekusagadzikana, sezvatatoona, vachiumba nyonganyonga; Aya mhirizhonga ane mhando uye mafomu asingaperi; Vazhinji vavo havasi periodic; Kureva kuti, havazvidzokorore munguva kana muchadenga, asi vamwe vanozviita. Iyi ndiyo nyaya yeVon Karman vortices yambotaurwa.