laminar flow

n. Nonturbulent flow of a viscous fluid in layers near a boundary, as that of lubricating oil in bearings.

laminar flow

n (General Physics) nonturbulent motion of a fluid in which parallel layers have different velocities relative to each other. Compare turbulent flow See also streamline flow

lam′inar flow′

n. the flow of a viscous fluid in which particles of the fluid move in parallel layers, each of which has a constant velocity but is in motion relative to its neighboring layers. [1945–50]

lam·i·nar flow

(lăm′ə-nər) Movement of a fluid in which the motion of the particles of fluid is very orderly and all particles move along straight lines in the same direction. Laminar flow is common in viscous fluids, especially those moving at low velocities. Compare turbulent flow.

Thesaurus

Noun

laminar flow - nonturbulent streamline flow in parallel layers (laminae)streamline flow - flow of a gas or liquid in which the velocity at any point is relatively steady

Translations

laminar flow

Laminar flow

A smooth, streamline type of viscous fluid motion characteristic of flow at low-to-moderate deformation rates. The name derives from the fluid's moving in orderly layers or laminae.

The chief criterion for laminar flow is a relatively small value for the Reynolds number, Re = &rgr;VL/μ, where &rgr; is fluid density, V is flow velocity, L is body size, and μ is fluid viscosity. Laminar flow may be achieved in many ways: low-density flows as in rarefied gases; low-velocity or “creeping” motions; small-size bodies such as microorganisms swimming in the ocean; or high-viscosity fluids such as lubricating oils. At higher values of the Reynolds number, the flow becomes disorderly or turbulent, with many small eddies, random fluctuations, and streamlines intertwining. See Creeping flow, Reynolds number, Turbulent flow, Viscosity

Nearly all of the many known exact solutions of the equations of motion of a viscous fluid are for the case of laminar flow. These mathematically accurate descriptions can be used to give insight into the more complex turbulent and transitional flow patterns for which no exact analyses are known. See Navier-Stokes equation

The theory of viscous lubricating fluids in bearings is a highly developed area of laminar flow analysis. Even large Reynolds number flows, such as aircraft in flight, have regions of laminar flow near their leading edges, so that laminar flow analysis can be useful in a variety of practical and scientifically relevant flows. See Boundary-layer flow, Fluid flow

Laminar Flow

an ordered flow of a liquid or gas, in which the fluid moves in layers parallel to the direction of flow. Laminar flow is observed in very viscous fluids. It also occurs when the velocity of flow is sufficiently low and during the slow flow of a liquid around small objects. Specifically, laminar flow occurs in narrow (capillary) tubes, in the lubricant layer in bearings, and in the thin boundary layer that forms near the surface of a body over which a fluid is flowing. If the velocity of flow of a given fluid is increased, the laminar flow, at a certain instant, may undergo a transition to a disordered turbulent flow. As this occurs, the resistance to the motion of the fluid is changed drastically. The mode of flow of a fluid depends on the Reynolds number Re. If the value of Re is smaller than a certain critical value Ren, then laminar flow occurs. If Re > Re_cr, then the flow can become turbulent. The value of Re_cr depends on the type of flow being considered. For instance, for flow through circular tubes, Re_cr ≈ 2,200 (if it is assumed that the characteristic velocity is the velocity averaged across the cross section of the tube and that the characteristic dimension is that of the tube’s diameter). Consequently, at Re_cr < 2,200, the flow of the fluid in the tube will be laminar. The output of liquid from a tube during laminar flow is determined by the Poiseuille law.

REFERENCES

Targ, S. M. Osnovnye zadachi teorii laminarnykh techenii. Moscow-Leningrad, 1951.
Loitsianskii, L. G. Mekhanika zhidkosti i gaza, 3rd ed. Moscow, 1970.

laminar flow

[′lam·ə·nər ′flō] (fluid mechanics) Streamline flow of an incompressible, viscous Newtonian fluid; all particles of the fluid move in distinct and separate lines.

streamline flow

The flow of a liquid or gas past a solid body in a manner so that the velocity of the fluid, at every point, does not change with time.

laminar flow

The flow of air over a surface in smooth layers and without any turbulence or cross flow of layers of air. See laminar boundary layer.

laminar flow

flow

[flo] 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 capacity" >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 flow" >maximal midexpiratory flow. Called also forced expiratory flow rate.laminar flow smooth, uninterrupted flow as of a gas through a tube.maximal expiratory flow FEF_200–1200; the rate of airflow at capacity" >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 FEF_25–75; the maximum rate of airflow measured between expired volumes of 25 and 75 per cent of the vital capacity" >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.

lam·i·nar flow

the relative motion of elements of a fluid along smooth parallel paths, which occurs at lower values of a Reynolds number.

lam·i·nar flow

(lam'i-năr flō) The relative motion of elements of a fluid along smooth parallel paths, which occurs at lower values of a Reynolds number.

laminar flow

laminar flow

laminar flow

lam′inar flow′

lam·i·nar flow

laminar flow

Laminar flow

Laminar Flow

REFERENCES

laminar flow

streamline flow

laminar flow

laminar flow

flow

lam·i·nar flow

lam·i·nar flow

laminar flow

Words related to laminar flow

noun nonturbulent streamline flow in parallel layers (laminae)

Related Words