CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '91355af869924d2d',cH: 'NhDYsB4UhInBIzX.PB4YFiS4b3U8YAYLgs7iU.oexcM-1739790882-1.2.1.1-arozDHFWLcUkAGMpJJmbV_KuIgILkL00ZpMA0CVBreSJ1FICb.32nmts3V_gZDMw',cUPMDTk: "\/abstracts\/17407\/turbulent-flow-in-corrugated-pipes-with-helical-grooves?__cf_chl_tk=Fdu2SR7WQ0os6uXSiFvNa0bA.Ape2IL_CNCM7J0ZeRk-1739790882-1.0.1.1-HAKsu5j4XGZFml7mu_eDi38iWj6pGmr87UKn81dBR90",cFPWv: 'b',cITimeS: '1739790882',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/17407\/turbulent-flow-in-corrugated-pipes-with-helical-grooves?__cf_chl_f_tk=Fdu2SR7WQ0os6uXSiFvNa0bA.Ape2IL_CNCM7J0ZeRk-1739790882-1.0.1.1-HAKsu5j4XGZFml7mu_eDi38iWj6pGmr87UKn81dBR90",md: "bsB6uiQJ6D2qz7rgY.u7JmcN2aubEr40UeWqsEnYJns-1739790882-1.2.1.1-4L2OrziUBWe51syIF9MlJAhyLYSpS2SiovOofkL_3w_tVR6qYCM8BKT3EkXuPod0rLpC6cW2YKg9glVvNB98QjoytBy0UehGHqD9kAUlriQuWQB1CtbkgMVjNj7fhmrTO7en_qHtklo54wbIvMInasBKZ3pBmUjXs39F9uDKoHovnxc9QVYRPb2Ojk3DlcWcH63wfXLt.w99kiEpsuAtmIGK8I0NwtlFnbwMzqiDmgexcFkOFnabBuquZR6SJ5hZ3Yw3kbSz8aQnDgQN_JHGNYNxULtN_JbTxzm2B7TX.Q1LEZUyHtz5R08eZduMOCtUTLBS4GhIhtK1ml9P4KfhjbHpASN3QArr5Y6H2HzpNp.iLBOi.yzr4XhjNoF7yZ0sfk_7ZG7MK6VaGum7vTDSCH_5Pbx8kAeB1CyTLzsllcrsKT_9LPn8TOwHNtPah233EKPKemx_T1vs3ElfNK17O6HcSOVKeMjTA78.M.gsnlB9UglOuNv9vBGwZ.UieELQUhFdnpJOkz.OppgZ_tyVqY_9T3AX9yNbaorIB7zlAQKhA2SDcHdPvs4TDpwjmbAxvQ22OgWR9TSIvNcTgTgT3R8hMlsliAkxRcWlb1QFYjW9cE5h4WuBs4t76I.5L3p8zjn3Qw2VFnelxAFw5yaPkr3ogVNaJeHjGdW56cMb3oFrQgXFbCrKfdVhw4CquwLit8kWELjptvLABpbJgZYhIkbHiqXM4SfaPNa12DYd5AjsZWhalthv_jbJhYKBAwaDqD6ibTnkZC4YJxS8lj02z0i_d6W4sGXzHeJU_QnNdMyk6KRHpDTXbmwQe1lizU40Jzh4BuGyE41ZNIRFu86A41rwcmfUw2JGiSsh0ibQ.pUL.WnOFSNTk_tCxDIBKEjf0Hu8Y6EfK9I_4hYvFYccHCg.Jx_v_JmimKyA_FlWR1pbWoiJbEjsyzx9.iOQ5E2SdY6lB_FkSMIjBgS0d9nia9HVrEkedPap.EN_.ib3hiKQtmoZQGaFNDxfPyyZ8BK5W1wPKD9MH52p78OkycqHHjJdjA5EBbKex9xXw3oylSNBJfbDX3B3d08xxhgazPfTKSFAt76_pqEReT8Fl93bB96qMtEorfddtMqB1DCC_8qAQoqRxnSKSyss0nsNZ4v9A6.yzoR5fnrd1J.WVd3jn4UJys4Jargz1Gm1rGTAyXHVZmNVEnfRG5Xt24tuAQIBjOPYhav6rgqrBauH.k9SAWOjLUFd9.AO.5c4lG6YpT1MwIxgMqJYQKy81ibgX_orblG2xpN6WChHtnCTv6xSWPplnNMG_BYTerLAIsxG_Qlsauw35o5ZclDSxgGn9I1Aza2uTUKG4J10XIhfasjvcQo2Kygc_95hhMixz2bNugGdLoToWtSMl17TnNIOBOtOl.h875WUFqw0_beC3J4BAMKWnpLwPwyfIzhOY7YBxwMjCFRXGncMuL.Dv0WrbF.H1BpG3qkNxwXxmzPefzkDhgXAwBWh3yWBkyjREq_0alRQOCXRyYL03bRMzmzSfkKNbahrukYS6B9yMePNtq45IkQXW1iLKdhV.CPj2QYZdukX0ZwZzt2EP4A0mqv1ZEUvT1Xm9GIPO1Sulfadm04dJrPqqfDerSjVxujIYCtU.07zgl0ywj6bexhrko4EMNEdC5LiesGGr3_egVqQnz2IwEYCzJ02F1zACWJu8dsOGO6ev4wOGT6oPb9JwYvVEEKR51rqWeyOB5XsfW0rtxwsCGigA9iyTbbYWzS7qwgdkcRzZ8Y9t8RrkVMUGlLviASgAuqylIj20kEdC7fdJSaoTBGKdZ6.iR6vKkx27q2bmPtpdHOdnNxnkMY8gejCY.CHhQ6YA4JwIQynAfVPtuZ8s4YwXT2ZITs8q7tXRpp3L5RI4oTr_CGWo5mOBp.mmj3_fdm4mQvPhC.wXeP0PKLNd6G9Ohz5D0Wz1mS1Ahq0PqXdxsMWmky0zL0LNZWfBbcaTose3ttY9Q9nTaqi9v_C3bBnMahceWMinuGquVnwT_edu808MhOYDDea4l9uvur.",mdrd: "38PCtQTb0daBrYVCFvH2CUVAJjCmYQhMzlPkslbW2U0-1739790882-1.2.1.1-hRAJ2DVSMeL01diyKer8SPBCnk0PdQk0eMXBqXXwlZZmPfP1Lh2o8Wx.niI1morGzKGZY_TRicCDPQNDvrNRk77bkZwDUiLv6FTfBRu8tAh61ARzngIMNRe_RpJV.tqpXKG6HgNLDMuyI83SHR7R5Ang7OMHuGLX3hCX6pLITzn6y6QIbouaoezf5mbMe1gVW5c5xwt6RgRl1lzGncd4odgOsMxoRvafwRsOIrB9vzOiORrxCdZihKDpBjKjSxdfA1UEIS.6X43gOVc0ah1vOhalEJbgArEFsJZ3CFwMK3diJaOX6s97ePzgHLcp9RannwPWFu_PbsISfu5oXjkq5TDW2WbXDsM3W06PjOdY.ypXD2qIIaGLivol_rLpgrlEhLmj4hm7x148KLeHCylsjZ_YDGsP4XbBEk5d2Q6WwRYHCQgqDNHGEgc1d1F7ZkGNfid9lXYPvGRDCcMsZnNigv20JL87OyRf0N99HiM1jzmnWcTMG.VkuHfD2cz_RNKCi4IyJUcxvvXi0geY7_vMP6OZVdUYZ8h9Wy2Eg6E.oCmvhbSaROcZlGHPQ1GbIsdPJssFTOpFz9b3OkO0L59BA.HQh.zX7h3FP.Uz1eKir8tE9scEiDW1S.Ni_0vlI7CmdWbn5uKUwSP9apbzBvI3IGW6OF7SwL_nvhRpFF8_sU81vK1EPk_ocTOdANAE4ASFGJGfM5H3m2SgD1ZSnN6en7CcqJsEerK1dc_wQfp4bEi0oYc4.a7KlVnjG7PsZ0gaBkk_43XPUwEnvvynsIHdp_gbARlaHVGImXvs32myZjSXjGhYraAepVQZcq9jk6DliqkhiAMY2trRgBP6PfJxUAG4kxWQB8XzSQYdRctZX1ShPfEuXN8TcVzWZaBIszjjCxn1RCYkPTpJWMHfFvJbPLLUqGiCN0HI_N_3kxG3vfFcRQheA9EUgjOpk6uOmXGhkvccjHo762fAPzPE8eDt9Iz0.5Trr7DLcNgvO2QPS.JMlYeSR73mTZT6Tddh3gtjX5ZQBHka6yGFNgw0L6ss2eHghBbkBrYLzQ5y4VDym67aNXlIneiyDWQ2SdZeOjlDdimOrTipKJdQY9d59W3i0wN5tRSI24_Z8JtjMdN5Fhjx1IbSpwV29FvEkw2GK1ySZCfYijPOqMVfP0YjHYVlOGohFZBlcQIk89MbG26zwIz.yZllHg_B8IqKSulwmIPWFwVMHEjmCHeJAVUbMe.eIfpZubQPB4NiGkdBfQjUdjAHJDGmoYox2FK.53LNc_ZAwWwe5YN74Dc1P7Y9MzDEDhvA4kVUQzz13.GjE_gO0VmxjhRlRLqQCxshr3c50bTyAOqMnZr.yFTnomTjkrNkNYzGPsb5sKqcRPck39a.Z3IWqHLFedibzmj0qokihm.aketkSYk4.K3CeM1TBG.6FpY3LUL7aCwf5e9FMvORju6SZu.dVMXDRMF34y_kqFVp1DLHUOlczta6W1h._8AEhLEE3HQo_K6n.c6Qw.XlMfRk.t0.REQJTc09tYIvVSwJva9.EBWLZ1rSgrTESkYlzjOq43twiQFyXV6K8csM0NgkfVzVWXEIXLZarMiSCmgiSP97mvgqyqWxPSxJwMsBZIQ0nR3A27gntW4dC6xHXzziLuuwN_2ThLAaKl.F6952pr2D.wV6.zDb08FGIoYlAw90IGC9UsAvDBznHnRoS3OJpl1NmFLXYGwTzRSZEZN2tqxUULgy57ei1efoKgXa8M3M_zamHkKRvmt3kbsFqAHM443PpDWj8RxPbo_uwILG5i_8mE9OYgYnUVyOLJuHrJ2ZMVoLzC02LuK52SZePCGv9SgR228mjre0h07muFetLX2tusDCLbQ4QAHGzK.bPMqCpEJDOx.i_kMk01UOYhyrzbrc1.AWMWzFWsR2ew5SPknWUWjgMRdugTEZyXBpVTQOrMWCifFl7dTLoVEMGUykAdX8iKEssYYsOL.hmX2S86m.LjCAf_H.USD0aU.6Cw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91355af869924d2d';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/abstracts\/17407\/turbulent-flow-in-corrugated-pipes-with-helical-grooves?__cf_chl_rt_tk=Fdu2SR7WQ0os6uXSiFvNa0bA.Ape2IL_CNCM7J0ZeRk-1739790882-1.0.1.1-HAKsu5j4XGZFml7mu_eDi38iWj6pGmr87UKn81dBR90" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>