Fundamentals of Fluid Flow Flashcards

Path line

A line made by a single particle as it moves during a particular period.

Streamline

A line which gives the velocity direction of the fluid at each point along the line at a given instant, across which no fluid movement can occur.

Streamtube

A space formed when streamlines are drawn through a closed curve, creating boundaries across which no fluid particle can pass.

Laminar Flow

Fluid motion occurring when the velocity of movement is sufficiently low that individual particles follow well-defined paths that do not cross or intersect one another.

Converging Path Lines

Path lines in a non-parallel conduit that denote increasing velocity in each path line in the direction of flow.

Diverging Path Lines

Path lines in a non-parallel conduit that denote decreasing velocity in each path line in the direction of flow.

Turbulent Flow

A flow pattern in which separate particles or groups of particles follow irregular paths that keep crossing and recrossing one another to form an intricate pattern of interlacing lines.

Critical Velocity

The velocity of flow in a given conduit at which the transition from laminar to turbulent flow starts when attained and exceeded.

Steady Flow

Flow condition where the velocity, pressure, and other flow characteristics at a specific point in the fluid do not change with time.

Unsteady Flow

Flow condition where the velocity and other characteristics vary with time at a specific point in the flowing fluid.

Uniform Flow

Fluid motion where, within a certain length or reach of a stream, the mean velocity at every section is the same.

Non-uniform Flow

Fluid motion where, within a certain reach of a stream, the mean velocities at different sections are unequal.

Discharge (Rate of Flow)

The volume of fluid passing a cross section per unit time in a stream of flowing fluid, given by $Q = A V$.

Equation of Continuity

The mathematical equation expressing the principle of conservation of mass in fluid flow, stating that the mass of fluid passing any section per unit time is constant ($$\rho_1 A_1 V_1 = \