The character of transitional capillary flow is investigated using pressure-drop measurements and instantaneous velocity fields acquired by microscopic PIV in the streamwise–wall-normal plane of a 536 lm capillary over the Reynolds-number range 1,800 £ Re £ 3,400 in increments of 100. The pressure-drop measurements reveal a deviation from laminar behavior at Re = 1,900 with the differences betw...

We examined effects of eye position on auditory cortical responses in macaques. Laminar current-source density (CSD) and multiunit activity (MUA) profiles were sampled with linear array multielectrodes. Eye position significantly modulated auditory-evoked CSD amplitude in 24/29 penetrations (83%), across A1 and belt regions; 4/24 cases also showed significant MUA AM. Eye-position effects occurr...

A natural laminar flow airfoil has been developed jointly by NASA's Dryden Flight Research and Langley Research Centers a s a part of the aircraft energy efficiency (ACEE) program. A NASA flight program incorporating this airfoil into partial wing gloves on the F-111 TACT airplane was scheduled to start in May, 1980. In support of this research effort, Boeing has conducted a n extensive boundar...

It is commonly known that the intermittent transition from laminar to turbulent flow in pipes occurs because, at intermediate values of a prescribed pressure drop, a purely laminar flow offers too little resistance, but a fully turbulent one offers too much. We propose a phenomenological model of the flow, which is able to explain this in a quantitative way through a hysteretic transition betwe...

Laminar-turbulent breakdown in a swept-wing boundary layer is typically caused by secondary instabilities of steady crossflow vortices (CFVs). So far, boundary-layer suction for laminar flow control in three-dimensional boundary layers has been applied to reduce the crossflow and thus the growth of the primary vortices only. We investigate the influence of strong, localized suction (pinpoint su...

The lower solar atmosphere consists of partially ionized turbulent plasmas harbouring velocity field, magnetic field and current density fluctuations. The correlations amongst these small scale fluctuations give rise to large scale flows and magnetic fields which decisively affect all transport processes. The three fluid system consisting of electrons, ions and neutral particles supports nonide...

Laminar flame speeds of mixtures of ethane, ethylene, acetylene, and carbon monoxide with small amounts of hydrogen addition at both atmospheric and elevated pressures were experimentally and computationally determined. It was found that the approximate linear correlation identified previously between the laminar flame speeds and an appropriate definition of the amount of hydrogen addition for ...

Cystic fibrosis (CF) is a chronic progressive pulmonary disorder caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. A CF lung is generally characterized by obstructed airflow to an extent that leads to destruction of airway wall support structure. Airway resistance, resulting from both laminar and turbulent flow, is an important mechanical factor contrib...

Various classic icing codes have been developed and used by the aircraft manufacturers to predict the ice shapes evolution. These codes apply boundary layer integral analysis, based on sand grain roughness, to estimate the convective heat transfer coefficient around the iced airfoil and adopt abrupt transition between laminar and turbulent flow. In the present work, the integral analysis is als...

The use of laminar airflow systems for tissue culture offers real promise in the control of airborne contamination. Some of the theoretical considerations in testing, design, and operation have been presented (1, 2). It is the purpose of this note to compare the advantages of a laminar airflow system with the conventional bench top, and to discuss some of the unique problems of these units in t...