High resolution turbulence modelling of airflow in an idealised human extra-thoracic airway

Ball, Christopher; Uddin, Mesbah; Pollard, A.

doi:10.1016/j.compfluid.2007.07.021

Cited by 61 publications

(48 citation statements)

References 29 publications

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“…Stapleton et al (83) also evaluated the applicability of the RANS approach in a model of the oropharynx and concluded that the RANS k-ω model of turbulence, where the specific dissipation ω = ε/k is not accurate for particle tracking in the range of Reynolds numbers found in the oropharynx. Ball et al (6) evaluated four RANS models and found that the k-ω model was adequate for predicting the general flow features of the extrathoracic airway, with apparently better predictive performance than the other RANS models. The low Reynolds number k-ω model has hence been used by some in preference to k-ε (59, 117); however, as noted by Longest and Vinchurkar (59), the k-ω model is inadequate for simulating turbulent flows that are characterized by intermittent turbulent eddies.…”

Section: Moderate Rementioning

confidence: 98%

Airway Gas Flow

Tawhai

Lin

2011

Comprehensive Physiology

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Local characteristics of airflow and its global distribution in the lung are determined by interaction between resistance to flow through the airways and the compliance of the tissue, with tissue compliance dominating flow distribution in the healthy lung. Current understanding is that conceptualizing the airways of the lung as a system of smooth adjoined cylinders through which air traverses laminarly is insufficient for understanding flow and energy dissipation and is particularly poor for predicting physiologically realistic transport of particles by the airflow. With rapid advances in medical imaging, computer technologies, and computational techniques, computational fluid dynamics is now becoming a viable tool for providing detailed information on the mechanics of airflow in the human respiratory tract. Studies using such techniques have shown that the upper airway (specifically its development of a turbulent laryngeal jet in the trachea), airway geometry, branching and rotation angle, and the pattern of joining of successive bifurcations are important in determining airflow structures. It is now possible to compute airflow in physical domains that are anatomically accurate and subject specific, enabling comparisons among intersubjects, that among subjects of different ages, and that among different species.

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Section: Moderate Rementioning

confidence: 98%

Airway Gas Flow

Tawhai

Lin

2011

Comprehensive Physiology

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“…Ball et al (2008) commented that the complex structures generated in the mouth-throat are in fact carried down the trachea and need to be accounted for when studying the flow in the lungs. Choi et al (2009) compared LESs of the same subjectspecific lung geometry with various levels of upper airways truncation.…”

Section: Introductionmentioning

confidence: 98%

“…This approach has been applied broadly to both the bronchial tree [for example, in the symmetric model of Weibel (1963) and the asymmetric model of Horsfield et al (1971)] and the extrathoracic region [e.g., the mouth-throat model introduced by Stapleton et al (2000)]. The relative simplicity of such configurations allows more straightforward meshing and calculation of a flow solution (Longest and Xi 2007;Ball et al 2008) and may ease the physical/optical access in experimental studies (Theunissen and Riethmuller 2008;Heenan et al 2003). These studies have provided fundamental insight into the airflow patterns found in situations typical of the respiratory system, such as branching networks, curved/tapered passages, and collapsible tubes (Pedley 1977;Chang and Menon 1985;Grotberg 1994).…”

Section: Introductionmentioning

confidence: 98%

Three-dimensional inspiratory flow in the upper and central human airways

et al. 2015

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“…They confirmed the existence of the secondary flow and Taylor-Görtler vortices that are associated with high wall turbulent shear stress. Ball et al (2008) used DNS with the lattice Boltzmann method to simulate the airflow inside an idealized human upper airway with a short upper part of the trachea. The simulations were performed for a steady 10 L/min airflow (which is a very low flow rate; for values below 12 L/min, a laminar regime is generally assumed) and no inhalation wave.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

Elcner

Lízal

Jedelský

et al. 2015

Biomech Model Mechanobiol

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In this article, the results of numerical simulations using computational fluid dynamics (CFD) and a comparison with experiments performed with phase Doppler anemometry are presented. The simulations and experiments were conducted in a realistic model of the human airways, which comprised the throat, trachea and tracheobronchial tree up to the fourth generation. A full inspiration/expiration breathing cycle was used with tidal volumes 0.5 and 1 L, which correspond to a sedentary regime and deep breath, respectively. The length of the entire breathing cycle was 4 s, with inspiration and expiration each lasting 2 s. As a boundary condition for the CFD simulations, experimentally obtained flow rate distribution in 10 terminal airways was used with zero pressure resistance at the throat inlet. CCM+ CFD code (Adapco) was used with an SST k-ω low-Reynolds Number RANS model. The total number of polyhedral control volumes was 2.6 million with a time step of 0.001 s. Comparisons were made at several points in eight cross sections selected according to experiments in the trachea and the left and right bronchi. The results agree well with experiments involving the oscillation (temporal relocation) of flow structures in the majority of the cross sections and individual local positions. Velocity field simulation in several cross sections shows a very unstable flow field, which originates in the tracheal laryngeal jet and propagates far downstream with the formation of separation zones in both left and right airways. The RANS simulation agrees with the experiments in almost all the cross sections and shows unstable local flow structures and a quantitatively acceptable solution for the time-averaged flow field.

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High resolution turbulence modelling of airflow in an idealised human extra-thoracic airway

Cited by 61 publications

References 29 publications

Airway Gas Flow

Airway Gas Flow

Three-dimensional inspiratory flow in the upper and central human airways

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

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