| Section S | S index | 871-879 of 1376 terms |
|---|
|
stack effect—An effect due to heat sources within a local exhaust enclosure (stack) producing convective air currents with vertical velocities proportional to the rate of heat transferred to the surrounding air and to the height of rise of the heated air. When hot gases rise through a stack, the vertical stack exit velocity is proportional to the square root of the difference in the densities of the heated air column and that of an equal column of the surrounding ambient air.
|
|
stacking—The holding pattern of aircraft awaiting their turn to approach and land at an airport. Stacking aircraft one above the other has to be employed when weather conditions interfere with normal VFR direct landing approach to the extent that aircraft arrive at a more rapid rate than they are able to approach and land. Stacked aircraft are usually separated by a fixed altitude, and when the bottom aircraft lands all those in the stack drop down one altitude separation. Newly arrived aircraft take a place at the top of the stack.
|
|
staff gauge—A graduated scale placed in a position so that the stage of a stream may be read directly therefrom; a type of river gauge. Staff gauges may be painted on bridge piers and pilings, and painted wooden scales or enameled metal scales may be mounted on bridge piers, docks, trees, or specially constructed supports to be partially submerged by the stream at all times.
|
|
stage-discharge relation—Relationship between water level and discharge at a certain location in a stream or river, also referred to as a rating curve or uniform flow rating curve, expressed as a single valued function. Dynamic stage-discharge relationships, which form loop rating curves, occur when the stage is not just a function of the discharge, but is also a function of the variable energy slope.
|
|
stage—The level of the water surface in a stream, river, or reservoir, measured with reference to some datum.
|
|
staggered grid—A grid on which all of the variables are not predicted at all of the points but rather are interspersed at alternate points. Grids using certain types of staggering, such as between mass and the components of momentum in the horizontal, have been shown to possess superior numerical properties to those of unstaggered grids.
|
|
