Module: DrivingPhysics::ScalarForce

Defined in:
lib/driving_physics/scalar_force.rb

Class Method Summary collapse

Class Method Details

.air_resistance(speed, frontal_area: FRONTAL_AREA, drag_cof: DRAG_COF, air_density: AIR_DENSITY) ⇒ Object

Resistance Forces

  1. air resistance aka drag aka turbulent drag depends on v^2

  2. “rotatational” resistance, e.g. bearings / axles / lubricating fluids aka viscous drag; linear with v

  3. rolling resistance, e.g. tire and surface deformation constant with v, depends on normal force and tire/surface properties

  4. braking resistance, supplied by operator, constant with v depends purely on operator choice and physical limits as such, it is not modeled here

Note: here we only consider speed; we’re in a 1D world for now



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# File 'lib/driving_physics/scalar_force.rb', line 21

def self.air_resistance(speed,
                        frontal_area: FRONTAL_AREA,
                        drag_cof: DRAG_COF,
                        air_density: AIR_DENSITY)
  0.5 * frontal_area * drag_cof * air_density * speed ** 2
end

.all_resistance(speed, frontal_area: FRONTAL_AREA, drag_cof: DRAG_COF, air_density: AIR_DENSITY, rot_cof: ROT_COF, nf_mag:, roll_cof: ROLL_COF) ⇒ Object 



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# File 'lib/driving_physics/scalar_force.rb', line 53

def self.all_resistance(speed,
                        frontal_area: FRONTAL_AREA,
                        drag_cof: DRAG_COF,
                        air_density: AIR_DENSITY,
                        rot_cof: ROT_COF,
                        nf_mag:,
                        roll_cof: ROLL_COF)
  speed_resistance(speed,
                   frontal_area: frontal_area,
                   drag_cof: drag_cof,
                   air_density: air_density,
                   rot_cof: rot_cof) +
    rolling_resistance(nf_mag, roll_cof: roll_cof)
end

.rolling_resistance(normal_force, roll_cof: ROLL_COF) ⇒ Object

normal force is not always mass * G, e.g. aero downforce



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# File 'lib/driving_physics/scalar_force.rb', line 33

def self.rolling_resistance(normal_force, roll_cof: ROLL_COF)
  normal_force * roll_cof
end

.rotational_resistance(speed, rot_cof: ROT_COF) ⇒ Object 



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# File 'lib/driving_physics/scalar_force.rb', line 28

def self.rotational_resistance(speed, rot_cof: ROT_COF)
  speed * rot_cof
end

.speed_resistance(speed, frontal_area: FRONTAL_AREA, drag_cof: DRAG_COF, air_density: AIR_DENSITY, rot_cof: ROT_COF) ⇒ Object

convenience methods



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# File 'lib/driving_physics/scalar_force.rb', line 41

def self.speed_resistance(speed,
                          frontal_area: FRONTAL_AREA,
                          drag_cof: DRAG_COF,
                          air_density: AIR_DENSITY,
                          rot_cof: ROT_COF)
  air_resistance(speed,
                 frontal_area: frontal_area,
                 drag_cof: drag_cof,
                 air_density: air_density) +
    rotational_resistance(speed, rot_cof: rot_cof)
end