Ko te paipa kōhao he momo paipa he kōhao tōna i muri i te hurihuri. He mea noa: he paipa kōhao porowhita, he paipa kōhao porowhita, me ētahi atu. Ka tapaina ko te paipa kōhao nā te mea ka kitea te kōhao mārama i te wāhanga o te paipa. Ka taea e tēnei momo paipa te whakahaere i te rere o te wai mā roto i te pakitara o ēnei hanganga pōrearea, te whakaputa i ngā wāhi wehenga rere, me te hanga i ngā awhiowhio me ngā kaha me ngā rahi rerekē. Ko ēnei awhiowhio te mea e whakarerekē ana i te hanganga rere o te wai, e whakanui ana hoki i te pōrearea tata ki te pakitara, kia pai ake ai te tauwehenga kiriata whakawhiti wera convective o te wai me te pakitara.

a. Ngongo riu hurihuri Ko te ngongo riu hurihuri he huri i tētahi riu whakapae, i tētahi riu porowhita rānei me tētahi teitei me te hohonu mai i waho o te ngongo porowhita e ai ki ngā whakaritenga hoahoa, ā, ka hanga he rara whakapae e piri ana, he rara porowhita rānei ki te pakitara o roto o te ngongo, e whakaaturia ana i te Pikitia 1. Ka taea e te riu i te pakitara o waho me te riu e piri ana ki te pakitara o roto o te paipa te whakarei ake i te whakawhiti wera o te wai i ngā taha e rua o te paipa i te wā kotahi. He tino pai mō te whakapakari i te whakawhiti wera o te wai kotahi-wāhanga i roto i te paipa, me te whakarei ake i te hauhautanga mamaoa me te kiriata wai e koropupū ana te whakawhiti wera o te wai i waho o te paipa i roto i te whakawhiti wera.

b. He momo porowhita kotahi, he momo porowhita maha hoki ngā momo porowhita. I muri i te hanganga, ka puta he porowhita me tētahi koki porowhita i waho o te porowhita porowhita, ā, he rara pūkohu kei roto i te porowhita. Kaua te porowhita e tino hohonu. Ko te hohonu o te porowhita, ko te nui ake o te ātete rere, ko te nui ake o te koki porowhita, ā, ko te nui ake o te tauwehenga kiriata whakawhiti wera o te ngongo porowhita. Mena ka taea e te wai te huri i te porowhita, he iti noa te pānga o te maha o ngā miro ki te whakawhiti wera.

c. Ko te paipa whakawhiti-whakawhiti he mea hanga mā te hurihuri tonu i te wāhanga whakawhiti-whakawhiti. Ko te taha o waho o te paipa he awa whakawhiti e whakawhiti ana i te tuaka o te paipa i te 90°, ā, ko te taha o roto o te paipa he rara pikopiko. I muri i te rere o te wai i roto i te rara pikopiko i roto i te paipa, kāore e puta he rere porowhita, engari ka puta he rōpū awhiowhio tuaka i te taha katoa o te wāhanga, kia kaha ake ai te whakawhiti wera. He pānga kaha anō hoki tō te ngongo miro whakawhiti ki te whakawhiti wera koropupū kiriata o te wai i roto i te ngongo, ka taea te whakanui ake i te tauwehenga whakawhiti wera koropupū mā te 3-8 ngā wā.