1. Static drift

• Fr = 0.138 (□), 0.280 (○), 0.410 (∆)

• Drift angle:

•                            β = -20 ~ 20 deg. for Fr = 0.138 and 0.280

•                   β = -12 ~ 12 deg. for Fr = 410

X	Y	N

• X is quadratic with β,

• Y and N are cubit with β,

as per Abkowitz (1966) mathematic model.