## Lecture 5-1: Front Tracking (1/2)

The front is used to
Update the momentum
Update the material properties
Enforce incompressibility
Update the pressure
None of the above

For an interface described by ordered points
The connectivity is determined by the order of the points
Points cannot be added or deleted
Points are always spaced equally
None of the above

For a closed interface the ghost points are set such that
point 1 is equal to point Nf
point 1 is equal to point Nf+1
point Nf is equal to point Nf+2
point Nf is equal to point 1
None of the above

To find the grid points next to a given front point we use
IF statement
MOD statement
INT statement
FLOOR statement
None of the above

Linear interpolation in two dimensions
Can be interpreted as area weighting
Includes only two points in each coordinate direction
Ensures that the interpolated values are bounded by the grid values
All of the above
None of the above

To interpolate the velocity of the front points we
Loop over all the points on the fixed grid to find the closest front point
Loop over all the points on the front to find the closest grid point
Compute the distance of every grid point from a given front point
Compute the distance of every front point from a given grid point
None of the above

An interface described by ordered points
Is moved by advecting the points
Is moved by velocity interpolated from the fluid grid
Is moved by the fluid velocity
Retains the point order as it is moved
All of the above

As rule of thumb, it is desirable to have
1-2 front points per grid spacing of the fluid grid
2-3 front points per grid spacing of the fluid grid
2-4 front points per grid spacing of the fluid grid
Less than 3 front points per grid spacing of the fluid grid
More than 6 front points per grid spacing of the fluid grid

When we add and delete grid points we
Redistribute the points so the distance between then is equal
Remove points if the distance between them is too large
Add points if the distance between them is too small
Add points if the distance between them is too large
None of the above

When we copy points back into the original array we
Do not copy the point if it is too close to the previous point
Add a point if the distance is too large
Copy the point if the distance is neither too large nor too small
All of the above
None of the above