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1. the movement of a liquid or gas.
2. the amount of a fluid that passes through an organ or part in a specified time; called also flow rate.
forced expiratory flow (FEF) the rate of airflow recorded in measurements of forced vital capacity, usually calculated as an average flow over a given portion of the expiratory curve; the portion between 25 and 75 per cent of forced vital capacity is called the maximal midexpiratory flow. Called also forced expiratory flow rate.
laminar flow smooth, uninterrupted flow as of a gas through a tube.
maximal expiratory flow FEF200–1200; the rate of airflow at forced vital capacity, represented graphically as the slope of the line connecting the points 200 mL and 1200 mL on the forced expiratory volume curve. See also pulmonary function tests. Called also maximal expiratory flow rate.
maximal midexpiratory flow FEF25–75; the maximum rate of airflow measured between expired volumes of 25 and 75 per cent of the vital capacity during a forced expiration; represented graphically as the slope of the line connecting the points on the forced expiratory volume curve at 25 and 75 per cent of the forced vital capacity. See also pulmonary function tests. Called also maximal midexpiratory flow rate.
renal plasma flow (RPF) the amount of plasma that perfuses the kidneys per unit time, approximately 90 per cent of the total constitutes the effective renal plasma flow, the portion that perfuses functional renal tissue such as the glomeruli.
turbulent flow flow that is agitated or haphazard.
tur·bu·lent flow(tŭr'byū-lĕnt flō)
A flow of gas characterized by a rough-and-tumble pattern; all molecules proceed at the same velocity, and resistance to flow is increased when compared with laminar flow.
turbulent flowthe flow of a medium (e.g. air or water) in which the molecules are moving in a random, non-ordered manner. Can be an effect of an object or body travelling through the medium.
turbulent flowswirling/eddying of blood flow through a narrowed blood vessel or one with a roughened tunica intima (e.g. atheroma); uneven blood flow increases intimal shear stresses, increasing atheroma and clot formation
occurs in blood vessels where there is a stenosis or aneurysm or where there is a sudden increase in velocity; the laminar flow of normal tubes is disrupted and the fluid is randomly and completely mixed; turbulent flows have a greater apparent viscosity than laminar flows.