pressure gradient

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pressure gradient

[′presh·ər ‚grād·ē·ənt]
(fluid mechanics)
The rate of decrease (that is, the gradient) of pressure in space at a fixed time; sometimes loosely used to denote simply the magnitude of the gradient of the pressure field. Also known as barometric gradient.
(meteorology)
The change in atmospheric pressure per unit horizontal distance, usually measured along a line perpendicular to the isobars.

Pressure Gradient

 

the change in atmospheric pressure per unit of distance along a normal toward an equal pressure surface (isobaric front) in the direction of a decrease in pressure.

Horizontal pressure gradients are commonly used in meteorology—that is, horizontal components of pressure gradients established at sea level or at another level. In this case, the isobaric normal toward an isobar is taken at a given level. Normally a horizontal pressure gradient is 1–3 millibars per 100 km, but in tropical cyclones the gradient sometimes reaches tens of millibars per 100 km (1 millibar = 100 newtons per sq m). The concept of a barometric grade is often used instead of the vertical pressure gradient.

pressure gradient

pressure gradientclick for a larger image
Pressure gradient.
The change in pressure with horizontal distance at a fixed time. The higher the pressure gradient, the faster is the fluid flow.
References in periodicals archive ?
As the vacuum time and dyeing time increased, color change and dye uptake first gradually increased until water began to be discharged, leading to a decrease of the pressure gradient in the log, and then decreased.
First, the value for height (h) does not appreciably change because the flow through the tracheobronchial tree originates from the pressure gradient between the mouth and the alveoli.
Although it can be invasive and uncomfortable for the patient, renal venography combined with measurement of the pressure gradient between the left renal vein and the IVC is the gold standard for demonstrating renal vein hypertension.
The fluid is driven by a uniform pressure gradient parallel to the channel plates and the entire flow field is subjected to a uniform inclined magnetic field of strength [H.
Rated to 450 deg F (232 deg C) the PressureXpress-HT tool provides accurate pressure gradients and overall data quality not achievable by conventional high-temperature formation tester tools.
Synoptic charts emphasized the divide between sub-Tropical and Temperate with stormy conditions south of the Cape which have been restricted from much northward extension, yet with excessive pressure gradients recurrent across the Southern Ocean southward to the Polar zone.
Of the 2 patients (#4 and #5 in the Table) who had both first and second CABG procedures at BUMC, both had small (16 mm Hg in #4 and 8 mm Hg in #5) peak systolic pressure gradients between the left ventricle and aorta at the time of the second isolated CABG procedure.
1995) considered, as in this study, that this circulation in large stratified lakes is a result of isotherm shape near the lake bottom, causing internal pressure gradients resulting in geostrophic cyclonic circulation.
In what follows the measurement locations, pressure differences, pressure drops, and pressure gradients are referenced with respect to their axial position relative to the inlet and outlet of the U-bend.
Patients with cirrhosis and esophageal varices have hepatic venous pressure gradients of 10-12 mm Hg.