Summary: Water And Air Flow Numerical Techniques

Read the summary and the most important questions on Water and Air Flow Numerical Techniques

• Lec: Introduction + FD

  This is a preview. There are 21 more flashcards available for chapter 04/01/2021
  Show more cards here

• There's various types of flow models, what is ours called?

  Environmental flow models

• How do we describe environmental flow models?

  In terms of balance equations, where balance equations are defined as fluxes

• Name 3 techniques that can be used to solve environmental flow models? Describe their characteristics

  
  

  • Finite differences (solving equations on a spatial grid at the node)
  • Finite volumes (budgeting flow in control volumes; representative area attached to node)
  • Finite elements (budgeting flow in control volumes with more accuracy)

• How do internal and external fluxes differ?

  Internal: advection & diffusion within the system
  External: Spatial (2D) eg precipitation, line (1D) or point (locally) eg exit at water reservoir

• What is implied in finite volumes and why?

  Conservation of mass, as representative areas are attached to the node and the edges of this volume are budgetted

• What is the difference between state variables and parameters?

  State variable (s): change over time and describe state of system at certain time & space. 
  Parameters: given and fixed

• What do the terms of the advection/diffusion equation mean?

  1) change of state over time
  2) u: advection: transport with mean velocity
  3) D: diffusion: spread of molecules/turbulence

• What is an ODE as explained by Chiel?

  An equation that tells you how the state variable changes over time, as a function of the state variable itself and the time.

• Which form of ODE will we use in WANT, where s is the state variable?

  Ds/dt = f (t,s)

• Environmental flow models are often about storage change and fluxes. How is this represented in the simple reservoir model?

  Change in storage = sum of all fluxes