WIND ROSE

A diagram showing the relative frequency and sometimes the average speed of the winds blowing from different directions in a specified region.

Related Terms

COLD CRANKING SIMULATOR

An intermediate shear rate viscometer that predicts the ability of an oil to permit a satisfactory cranking speed to be developed in a cold engine. (CCS)

cold_cranking_simulator ccs viscometer cold_engine oil shear_rate speed cold rate shear

GRID TRACK

The direction of the track relative to grid north

grid_track relative direction grid grid_north north track

A device for determining the course and speed over the ground in shallow water consisting of a lead or weight attached to a line. The lead is thrown overboard and allowed to rest on the bottom. The course over ground is indicated by the direction the line tends and the speed by the amount of line paid out in a unit of time.

ground_log device water unit weight line overboard course speed ground lead course_over_ground direction rest shallow

HARMONIC

1. A sinusoidal quantity having a frequency that is an integral multiple of the frequency of a periodic quantity to which it is related. 2. A signal having a frequency which is an integral multiple of the fundamental frequency.

harmonic frequency signal sinusoidal

HELIOCENTRIC

Relative to the sun as a center

heliocentric relative

FRICTION

The resisting force encountered at the common boundary between two bodies when, under the action of an external force, one body, moves or tends to move relative to the surface of the other.

friction force boundary surface action relative

FRETTING

Wear phenomena taking place between two surfaces having oscillatory relative motion of small amplitude.

fretting wear surface oscillatory_relative_motion amplitude motion relative_motion relative place

BROOKFIELD VISCOSITY

Apparent viscosity in cP determined by Brookfield viscometer, which measures the torque required to rotate a spindle at constant speed in oil of a given temperature. Basis for ASTM Method D 2983; used for measuring low temperature viscosity of lubricants.

brookfield_viscosity brookfield_viscometer oil temperature viscosity astm speed constant torque apparent cp low spindle

GUST

1. A sudden brief increase in the speed of the wind of more transient character than a squall, and followed by a lull or slackening of the wind. 2. The violet wind or squall that accompanies a thunder- storm.

gust wind speed lull squall

HEAD TIDE

A tidal current setting in a direction approximately opposite to the heading of a vessel. One setting in such a direction as to increase the speed of a vessel is called a FAIR TIDE. One abeam is called a BEA

head_tide vessel current speed abeam direction fair heading setting tidal tidal_current