The text discusses various aspects of fluid dynamics, focusing on flow in different geometries such as pipes, planes, plates, and annular pipes. It delves into the concept of momentum transport, explaining that it comprises both molecular and convective momentum transport.
Solving equations of change for the Boundary layer gives friction factor and drag
Examples
Flow through annular pipe
Flow between plates
Flow in planes
Flow through pipe
Momentum Transport
Macroscopic balance
Meachanical energy balance
Momentum balance
Mass balance
Macroscopic Variables
External flow
Drag
Internal flow
Friction
Microscopic Balance
Methods
Equations of Change
Shell balance
Important Concepts
Velocity gradients in a flow are confined to a thin layer near the wall. This layer is called Boundary layer. by solving equations of change for this layer skin frictional loss can be calculated
The three levels of study of TP are related to each other
Momentum Transport = Molecular Momentum Transport + Convective Momentum Transport
Drag is the frictional force for external flow
Drag Coefficient
Skin friction loss is the frictional force exerted by fluid on the wall of a pipe (Ff-s). This is same as frictional loss calculated from Moody chart
Mechanisms
Convective Transport
Caused by Bulk flow by
Gravity
Pressure gradient
Molecular Transport
Pressure forces
viscous forces due to velocity gradients in flow
Tips for Test & Exam
Tip 10: Practice TP, Never study
Tip 9: For inclined planes and pipes, Learn to determine the component of gravity force acting on the flow
Tip 8: particle Re is Dp*V*rho / mu
Dp is particle diameter, whereas rho and mu are fluid properties
Tip 7: Pressure in the macroscopic momentum balance equation should be gauge pressure
Tip 6: checking dimensional consistency of equations will help avoid errors
Tip 5 : If you are taking 40 minutes or less for the microscopic momentum balance problem, the remaining 80 minutes should be enough for the other 3 problems
Tip 4: if pressure not known, do not assume, Check if Bernoulli equation can be used to find it
Tip 3: Always assign r to the radial coordinate and z to the axial coordinate in cylindrical systems
Tip 2: when to use equations of change and when to use shell balance?
The answer is: the choice is yours unless the question specifies the method. Given choice, I would prefer using equations of change. of course you need to justify when cancelling terms
Tip 1 : Please approach TP with an open mind. Get rid of all preconceived notions. Please talk to me to solve your problems / misunderstandings. The more you talk to me the more I can help
