Chapter 2 Flashcards
To understand various processes of transportation and deposition of sediment. (27 cards)
How does fluid density work?
Varies with fluid type
What is fluid viscosity?
The measure of the ability of fluid to flow
(See chapter 2 HW notes for formulas)
What is laminar flow?
A unidirectional fluid persisting in a straight stream with a nearly constant width.
velocity is constant
What is turbulent flow?
A constantly changing and deforming stream.
velocity is avg over time
What is a Newtonian fluid?
fluid viscosity is independent of changing velocity
What is a Non-Newtonian Fluid?
fluid viscosity is dependent on changing velocity
What is a bedform?
sediment structures controlled by fluids and flow of sediments that represent a depositional environment
What does flow type depend on?
Viscosity and velocity of fluid
What is Reynold’s number?
The ratio between a fluid’s inertial forces and it’s viscous forces
How does laminar flow affect a fluid’s Reynolds number?
It is small
how does turbulent flow affect a fluid’s Reynold’s number?
It is high
What is the critical range for Reynold’s number?
between 500 and 2000
what is meant by the critical range for Reynold’s number?
The transition between laminar and turbulent flow.
What is entrainment?
The movement of grain in fluid
What are the forces that move grains
Fd: Drag forces
Fl: Lift forces
these increase with an increase in velocity
(see chart in day 3 notes)
What are the 3 aspects of bedload?
Sliding, Rolling, and Saltation(bouncing)
why does it take the same amount of energy to move clay as a pebble?
Clays have electric charge that cause the particles to clump together.
What are the types of sediment transport?
Entrainment and transport by fluid
Transport by wind (similar to entrainment)
sediment gravity flow
Transport by wind
Low viscosity and low density’
can only deposit medium sized sand and lower sized grains
sands by bedload
silts/dust by suspended load
sediment gravity flow
movement down slope due to gravity
4 types depending on fluid characteristics and sediment load.
Grain flow
Cohesive sediment under force of gravity
and fluid acts as a lubricant
continues by grain to gran collision
(See chart in Sed day 3 notes)
What is a debris flow?
Dense mixture of mud and large grains (Cobble and Boulder) behaves as a Non-Newtonian fluid.
What is a mud flow?
A dense mixture of mud and grains smaller or equal to sand grains
(See charts on sed day 3)
What is a turbidity flow?
water that has suspended sediment and is denser than clear water.
