A tidal bore impacts significantly on the estuarine ecosystem, although little is known on the flow field, mixing and sediment motion beneath tidal bores. In the absence of detailed field measurements, a quasi steady flow analogy was applied to investigate an undular tidal bore with inflow Froude numbers 1.6 and 1.25. Experimental results indicated that rapid flow redistributions occur beneath ...

The hydrodynamics of distributary channels has tremendous impact on nutrient and dissolved oxygen circulation, transport of sediments, and delta formation and evolution; yet many processes acting at the river–marine interface of a delta are poorly understood. This paper investigates the combined effect of river hydrograph and micro-tides on the hydrodynamics of a delta distributary. As the rati...

A tidal bore is a positive surge propagating upstream as the tidal flow turns to rising in river mouths exhibiting a converging funnelled channel forms during low freshwater conditions. While some recent laboratory experiments brought new insights to the turbulent motion generated by tidal bores, a numerical model based upon the Navier-Stokes equations is proposed to investigate the complicated...

[1] We conduct laboratory experiments and direct numerical simulations on internal gravity waves generated by tidal flow over a model three‐dimensional Gaussian mountain on the sea floor. When 2w < N (where w is the tidal frequency and N is the buoyancy frequency), the flow generates second harmonic internal waves that propagate perpendicular to the tidal forcing direction. These unexpected har...

Observations of residual exchange flows at the entrance to four subtropical estuaries, two of them semiarid, indicate that these flows are mainly tidally driven, as they compare favorably with theoretical patterns of tidal residual flows. In every estuary examined, the tidal behavior was that of a standing or near-standing wave, i.e., tidal elevation and tidal currents were nearly in quadrature...

Our main aim was to determine an appropriate time for lung function measurements in infants, prior to environmental influences upon their respiratory tract. Tidal flow-volume loops, respiratory system compliance (Crs) and resistance (Rrs) (single breath passive occlusion technique) were measured in 24 healthy, awake awake infants, at one hour and on the following four days of life to investigat...

Regional expiratory flow limitation (EFL) may occur during tidal breathing without being detected by measurements of flow at the mouth. We tested this hypothesis by using Technegas to reveal sites of EFL. A first study (study 1) was undertaken to determine whether deposition of Technegas during tidal breathing reveals the occurrence of regional EFL in induced bronchoconstriction. Time-activity ...

The modelling of tidal turbines and the hydrodynamic effects of tidal power extraction represents a relatively new challenge in the field of computational fluid dynamics. Many different methods of defining flow and boundary conditions have been postulated and examined to determine how accurately they replicate the many parameters associated with tidal power extraction. This paper outlines the r...

The purpose of this study, in patients with chronic obstructive pulmonary disease (COPD), was to examine the relationship of dyspnoea, rated on a visual analogue scale (VAS), to 1) tidal ventilatory variables measured on exercise and 2) pre-exercise lung function. Twenty one patients (forced expiratory volume in one second (FEV1) mean (SD) 1.19 (0.32) l) were studied. During a preliminary test,...

The increasing availability of appliances for measuring lung function in infants may allow clinical and epidemiological applications. The aim of the present study was to establish reference values for tidal breathing lung function in awake newborn infants and to investigate potential sources of variability. Tidal flow-volume loops were measured in 803 awake, healthy infants (427 males and 376 f...