{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T00:13:20Z","timestamp":1783556000104,"version":"3.55.0"},"reference-count":28,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T00:00:00Z","timestamp":1778284800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T00:00:00Z","timestamp":1783555200000},"content-version":"vor","delay-in-days":61,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100004359","name":"Swedish Research Council","doi-asserted-by":"crossref","award":["2021-04894"],"award-info":[{"award-number":["2021-04894"]}],"id":[{"id":"10.13039\/501100004359","id-type":"DOI","asserted-by":"crossref"}]},{"name":"NIH\/NHLBI","award":["R33HL161814"],"award-info":[{"award-number":["R33HL161814"]}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Pulsating airflow jets delivered via nasal cannula offer a promising, comfortable, non-invasive alternative to continuous positive airway pressure (CPAP) for treating obstructive sleep apnea (OSA). However, the fluid dynamic mechanisms by which pulsatile flow influences upper airway pressure remain poorly understood in anatomically realistic geometries. This study used large eddy simulations (LES) to examine pressure and flow characteristics of pulsating nasal jets within a patient-specific upper airway model. Two airflow conditions were simulated: (1) steady high-flow nasal cannula (HFNC) at 40 L\/min and (2) pulsatile flow at 20 Hz with a 30% duty cycle, matched to the same mean flow rate. Each pulse generated a vortex ring that impinged on the nasal walls, creating localized high-pressure regions and asymmetric shear stress. Compared to steady flow, the pulsatile jet increased time-averaged pharyngeal pressure by up to 50%. Spectral analysis revealed that the 20 Hz pressure oscillations were primarily confined to the upper airway, with substantial attenuation through the pharyngeal\u2013laryngeal region and negligible coherent oscillatory content by the trachea. These effects, shaped by jet-wall interactions in complex anatomy, diverge from classical vortex dynamics. Pulsatile nasal flow may offer a precise, geometry-responsive method for upper airway stabilization, suggesting a path toward a more tolerable, mask-free alternative to CPAP for OSA therapy.<\/jats:p>","DOI":"10.1038\/s41598-026-52238-8","type":"journal-article","created":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T07:44:58Z","timestamp":1778312698000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Flow dynamics and pressure modulation in a patient-specific upper airway using a pulsating nasal jet"],"prefix":"10.1038","volume":"16","author":[{"family":"Muhammad Aseem","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elias","family":"Sundstr\u00f6m","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liran","family":"Oren","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,5,9]]},"reference":[{"key":"52238_CR1","first-page":"1","volume":"1","author":"P L\u00e9vy","year":"2015","unstructured":"L\u00e9vy, P. et al. Obstructive sleep apnoea syndrome. Nat. Rev. Dis. Primers. 1, 1\u201321 (2015).","journal-title":"Nat. Rev. Dis. Primers."},{"key":"52238_CR2","doi-asserted-by":"publisher","first-page":"862","DOI":"10.1016\/S0140-6736(81)92140-1","volume":"317","author":"C Sullivan","year":"1981","unstructured":"Sullivan, C., Berthon-Jones, M., Issa, F. & Eves, L. Reversal of obstructive sleep apnoea by continuous positive airway pressure applied through the nares. Lancet 317, 862\u2013865 (1981).","journal-title":"Lancet"},{"key":"52238_CR3","doi-asserted-by":"crossref","unstructured":"Hirshkowitz, M. & Sharafkhaneh, A. In seminars in respiratory and critical care medicine. 68-79 (Published 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New) (2005).","DOI":"10.1055\/s-2005-864209"},{"key":"52238_CR4","doi-asserted-by":"publisher","first-page":"263","DOI":"10.1136\/thx.49.3.263","volume":"49","author":"HM Engleman","year":"1994","unstructured":"Engleman, H. M., Martin, S. E. & Douglas, N. J. Compliance with CPAP therapy in patients with the sleep apnoea\/hypopnoea syndrome. Thorax 49, 263\u2013266 (1994).","journal-title":"Thorax"},{"key":"52238_CR5","doi-asserted-by":"publisher","first-page":"81","DOI":"10.1053\/smrv.2001.0197","volume":"7","author":"HM Engleman","year":"2003","unstructured":"Engleman, H. M. & Wild, M. R. Improving CPAP use by patients with the sleep apnoea\/hypopnoea syndrome (SAHS). Sleep Med. Rev. 7, 81\u201399 (2003).","journal-title":"Sleep Med. Rev."},{"key":"52238_CR6","doi-asserted-by":"publisher","first-page":"126","DOI":"10.1016\/j.aucc.2007.08.001","volume":"20","author":"N Groves","year":"2007","unstructured":"Groves, N. & Tobin, A. High flow nasal oxygen generates positive airway pressure in adult volunteers. Aust. Crit. Care. 20, 126\u2013131 (2007).","journal-title":"Aust. Crit. Care."},{"key":"52238_CR7","doi-asserted-by":"publisher","first-page":"886","DOI":"10.1093\/bja\/aep280","volume":"103","author":"R Parke","year":"2009","unstructured":"Parke, R., McGuinness, S. & Eccleston, M. Nasal high-flow therapy delivers low level positive airway pressure. Br. J. Anaesth. 103, 886\u2013890 (2009).","journal-title":"Br. J. Anaesth."},{"key":"52238_CR8","doi-asserted-by":"publisher","first-page":"335","DOI":"10.5664\/jcsm.7640","volume":"15","author":"SP Patil","year":"2019","unstructured":"Patil, S. P. et al. Treatment of adult obstructive sleep apnea with positive airway pressure: an American Academy of Sleep Medicine clinical practice guideline. J. Clin. Sleep Med. 15, 335\u2013343 (2019).","journal-title":"J. Clin. Sleep Med."},{"key":"52238_CR9","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1016\/j.clinbiomech.2019.04.004","volume":"65","author":"C Moore","year":"2019","unstructured":"Moore, C. et al. High flow nasal cannula: influence of gas type and flow rate on airway pressure and CO2 clearance in adult nasal airway replicas. Clin. Biomech. 65, 73\u201380 (2019).","journal-title":"Clin. Biomech."},{"key":"52238_CR10","doi-asserted-by":"publisher","first-page":"66","DOI":"10.1016\/j.clinbiomech.2017.11.003","volume":"66","author":"CP Moore","year":"2019","unstructured":"Moore, C. P., Katz, I. M., Caillibotte, G., Finlay, W. H. & Martin, A. R. Correlation of high flow nasal cannula outlet area with gas clearance and pressure in adult upper airway replicas. Clin. Biomech. 66, 66\u201373 (2019).","journal-title":"Clin. Biomech."},{"key":"52238_CR11","doi-asserted-by":"publisher","first-page":"376","DOI":"10.4172\/2161-105X.1000376","volume":"6","author":"T Miller","year":"2016","unstructured":"Miller, T., Saberi, B. & Saberi, S. Computational fluid dynamics modeling of extrathoracic airway flush: evaluation of high flow nasal cannula design elements. J. Pulm. Respir. Med. 6, 376 (2016).","journal-title":"J. Pulm. Respir. Med."},{"key":"52238_CR12","doi-asserted-by":"crossref","unstructured":"Oren, L., Gutmark, E. & Romaker, A. A novel method for positive airway pressure delivery: pulsating vortical airflow. Journal of Clinical Sleep Medicine 21, 513\u2013518 (2025).","DOI":"10.5664\/jcsm.11466"},{"key":"52238_CR13","doi-asserted-by":"publisher","DOI":"10.1017\/jfm.2023.501","volume":"967","author":"T Ahmed","year":"2023","unstructured":"Ahmed, T. & Erath, B. D. Experimental study of vortex ring impingement on concave hemispherical cavities. J. Fluid Mech. 967, A38 (2023).","journal-title":"J. Fluid Mech."},{"key":"52238_CR14","doi-asserted-by":"publisher","first-page":"1123","DOI":"10.1007\/s00348-011-1135-x","volume":"51","author":"LD Couch","year":"2011","unstructured":"Couch, L. D. & Krueger, P. S. Experimental investigation of vortex rings impinging on inclined surfaces. Exp. Fluids 51, 1123\u20131138 (2011).","journal-title":"Exp. Fluids"},{"key":"52238_CR15","doi-asserted-by":"publisher","first-page":"453","DOI":"10.1007\/BF00187063","volume":"7","author":"T Lim","year":"1989","unstructured":"Lim, T. An experimental study of a vortex ring interacting with an inclined wall. Exp. Fluids 7, 453\u2013463 (1989).","journal-title":"Exp. Fluids"},{"key":"52238_CR16","doi-asserted-by":"publisher","first-page":"2221","DOI":"10.1016\/j.jbiomech.2011.06.006","volume":"44","author":"M Mihaescu","year":"2011","unstructured":"Mihaescu, M., Mylavarapu, G., Gutmark, E. J. & Powell, N. B. Large eddy simulation of the pharyngeal airflow associated with obstructive sleep apnea syndrome at pre and post-surgical treatment. J. Biomech. 44, 2221\u20132228 (2011).","journal-title":"J. Biomech."},{"key":"52238_CR17","doi-asserted-by":"publisher","first-page":"1323","DOI":"10.1016\/j.mri.2012.05.001","volume":"30","author":"A Fedorov","year":"2012","unstructured":"Fedorov, A. et al. 3D Slicer as an image computing platform for the quantitative imaging network. Magn. Reson. Imaging 30, 1323\u20131341 (2012).","journal-title":"Magn. Reson. Imaging"},{"key":"52238_CR18","unstructured":"Cignoni, P. et al. in Eurographics Italian chapter conference. 129-136 (Salerno)."},{"key":"52238_CR19","doi-asserted-by":"publisher","first-page":"75","DOI":"10.1016\/j.amjoto.2007.02.002","volume":"29","author":"R Mladina","year":"2008","unstructured":"Mladina, R., \u010cuji\u0107, E., \u0160ubari\u0107, M. & Vukovi\u0107, K. Nasal septal deformities in ear, nose, and throat patients: an international study. Am. J.Otolaryngol. 29, 75\u201382 (2008).","journal-title":"Am. J.Otolaryngol."},{"key":"52238_CR20","doi-asserted-by":"publisher","DOI":"10.1088\/1752-7163\/ac2589","volume":"15","author":"JD Pleil","year":"2021","unstructured":"Pleil, J. D., Wallace, M. A. G., Davis, M. D. & Matty, C. M. The physics of human breathing: Flow, timing, volume, and pressure parameters for normal, on-demand, and ventilator respiration. J. Breath Res. 15, 042002 (2021).","journal-title":"J. Breath Res."},{"key":"52238_CR21","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1007\/s00211-009-0251-5","volume":"114","author":"H Abboud","year":"2009","unstructured":"Abboud, H., Girault, V. & Sayah, T. A second order accuracy for a full discretized time-dependent navier-stokes equations by a two-grid scheme. Numer. Math. 114, 189\u2013231 (2009).","journal-title":"Numer. Math."},{"key":"52238_CR22","doi-asserted-by":"publisher","first-page":"40","DOI":"10.1016\/0021-9991(86)90099-9","volume":"62","author":"RI Issa","year":"1986","unstructured":"Issa, R. I. Solution of the implicitly discretised fluid flow equations by operator-splitting. J. Comput. Phys. 62, 40\u201365 (1986).","journal-title":"J. Comput. Phys."},{"key":"52238_CR23","doi-asserted-by":"publisher","first-page":"1271","DOI":"10.1063\/1.1564600","volume":"15","author":"PS Krueger","year":"2003","unstructured":"Krueger, P. S. & Gharib, M. The significance of vortex ring formation to the impulse and thrust of a starting jet. Phys. Fluids 15, 1271\u20131281 (2003).","journal-title":"Phys. Fluids"},{"key":"52238_CR24","doi-asserted-by":"publisher","first-page":"729","DOI":"10.1017\/jfm.2017.878","volume":"837","author":"Y Xu","year":"2018","unstructured":"Xu, Y., Wang, J.-J., Feng, L.-H., He, G.-S. & Wang, Z.-Y. Laminar vortex rings impinging onto porous walls with a constant porosity. J. Fluid Mech. 837, 729\u2013764 (2018).","journal-title":"J. Fluid Mech."},{"key":"52238_CR25","doi-asserted-by":"publisher","first-page":"1755","DOI":"10.1061\/(ASCE)0733-9429(1984)110:12(1755)","volume":"110","author":"WC Hughes","year":"1984","unstructured":"Hughes, W. C. & Flack, J. E. Hydraulic jump properties over a rough bed. J. Hydraul. Eng. 110, 1755\u20131771 (1984).","journal-title":"J. Hydraul. Eng."},{"key":"52238_CR26","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijft.2023.100312","volume":"17","author":"RD Plant","year":"2023","unstructured":"Plant, R. D., Friedman, J. & Saghir, M. Z. A review of jet impingement cooling. Int. J. Thermofluids 17, 100312 (2023).","journal-title":"Int. J. Thermofluids"},{"key":"52238_CR27","doi-asserted-by":"publisher","first-page":"565","DOI":"10.1016\/S0065-2717(06)39006-5","volume":"39","author":"N Zuckerman","year":"2006","unstructured":"Zuckerman, N. & Lior, N. Jet impingement heat transfer: Physics, correlations, and numerical modeling. Adv. Heat Transf. 39, 565\u2013631 (2006).","journal-title":"Adv. Heat Transf."},{"key":"52238_CR28","first-page":"131","volume":"126","author":"CM Rossman","year":"1982","unstructured":"Rossman, C. M., Waldes, R., Sampson, D. & Newhouse, M. T. Effect of chest physiotherapy on the removal of mucus in patients with cystic fibrosis. Am. Rev. Respir. Dis. 126, 131\u2013135 (1982).","journal-title":"Am. Rev. Respir. Dis."}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-52238-8","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-52238-8.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-52238-8.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T23:14:03Z","timestamp":1783552443000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-52238-8"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,9]]},"references-count":28,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,12]]}},"alternative-id":["52238"],"URL":"https:\/\/doi.org\/10.1038\/s41598-026-52238-8","relation":{"has-preprint":[{"id-type":"doi","id":"10.21203\/rs.3.rs-7303826\/v1","asserted-by":"object"}]},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,9]]},"assertion":[{"value":"5 August 2025","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"4 May 2026","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"9 May 2026","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interest"}}],"article-number":"21288"}}