Fluid Flow Flashcards
What is a Streamline?
A streamline is an an imaginary line that can be drawn through the flow region so that velocity vectors of the flow are tangent to the streamline at each point of the flow.
What are the Flow Types?
One Dimensional Two Dimensional Three Dimensional Uniform or Nonuniform Steady or Unsteady Laminar or Turbulent
Explain One Dimensional Flow.
The changes in the flow are only considered in one dimension while the other two dimensions are assumed constant.
Explain Two Dimensional Flow.
Flow takes place in parallel two dimensions on identical paths.
Explain Three Dimensional flow.
Flow and flow conditions (pressure, temperature, etc…) Are described in all three dimensions.
Explain Laminar Flow.
Flow is so slow that no mixing of the fluid takes place. It acts as if thin layers of of fluid are sliding in parallel across each other.
Explain Turbulent Flow.
When regions of the flow move around in an unorderly fashion making the path difficult to predict.
Because there is a continuous interchange of momentum between molecules, the layers cannot move over each other as easily as in laminar flow. The effective viscosity in turbulent flow is higher than for the same fluid in laminar fashion.
Explain Ideal Flow.
Ideal Flow is flow which has no viscosity.
Explain Steady Flow.
Steady flow is when the conditions do not change with time. Velocity, pressure, density and temperature remain constant from one moment to the next. It can differ from point to point though.
Explain Unsteady Flow.
Unsteady Flow is when conditions change with time.
Explain Uniform Flow.
Uniform flow is when the velocity, in size and direction, is the same everywhere. Velocity can change with time and other conditions may change from point to point.
(e.g. water flowing in a pipe of constant diameter.)
Explain Non-Uniform Flow.
Non-Uniform Flow is when velocity, in size and direction, differs from point to point.
(e.g. water flowing through a converging nozzle.)
What is the first law of thermodynamics?
Energy cannot be destroyed but only converted from one form to another.
What is the Conservation of Momentum?
The sum of all external forces in a certain direction which acts upon a fluid in a control volume is equal to the mass flow rate through the control volume, multiplied by the velocity change in the same direction.
What is the conservation of mass?
The mass flow rate in is equal to the mass flow rate out.
m1 = m2
