def dist4(V_BIKE, V_WIND, GRADE, G_FRAC, debug, C_SF):
total_s = 0
DELTA_V = 0.05 # m/sec
v_i = common.meter_per_second(V_BIKE) # convert from kmph to m/sec.
delta_e = get_delta_ke(v_i, v_i - DELTA_V)
drag_forces = get_total_res(common.kmph(v_i), V_WIND, GRADE, G_FRAC, debug, get_rear_frac(G_FRAC), C_SF)
delta_s = delta_e / drag_forces
while (v_i > 1.0): # repeat till velocity is 1 m/s
v_f = v_i - DELTA_V
v_a = (v_f + v_i) / 2.0 # average velocity
delta_t = delta_s / (v_a) # time interval
drag_forces = get_total_res(common.kmph(v_f), V_WIND, GRADE, G_FRAC, debug, get_rear_frac(G_FRAC), C_SF)
if (drag_forces < 0):
return -1
delta_ke = get_delta_ke(v_i, v_f)
# calculate delta pe using delta s, positive when gradient is uphill and negative for downhill
delta_pe = TOTAL_MASS * G_ACCEL * (GRADE / 100.0) * v_a * delta_t
#delta_pe = TOTAL_MASS * G_ACCEL * (GRADE / 100.0) * delta_s
# calculate the drag forces as F * d_s = d_e, delta_ke will be negative when slowing down
# d_e is the total energy lost
delta_e = delta_ke - delta_pe
delta_s = delta_e / drag_forces
total_s = total_s + delta_s
v_i = v_f
if (debug):
print ("TE: " + common.nice_s(delta_e) + " KE: " + common.nice_s(delta_ke) + \
" PE: " + common.nice_s(delta_pe) + " Drag Forces: " + common.nice_s(drag_forces) + \
" DS: " + common.nice_s(delta_s) + " DT: " + common.nice_s(delta_t))
return total_s
def calc_dist(V_BIKE, V_WIND, GRADE, G_FRAC, debug, return_dist, rear_frac, C_SF):
if (rear_frac == INVALID_REAR_FRAC):
rear_frac = get_rear_frac(G_FRAC)
TOTAL_RES = get_total_res(V_BIKE, V_WIND, GRADE, G_FRAC, debug, rear_frac, C_SF)
DELTA_TIME = 0.05 # seconds
total_time = 0
velocity = V_BIKE
iter = 0
stopping_dist = 0
while (velocity > 1):
# calculate the drag force, new acceleration, new velocity, and cumulative stopping distance
TOTAL_RES = get_total_res(velocity, V_WIND, GRADE, G_FRAC, debug, rear_frac, C_SF)
if (TOTAL_RES < 0):
return -1
accel = TOTAL_RES / TOTAL_MASS
new_velocity = velocity - common.kmph(accel) * DELTA_TIME # convert accel from m/s to kmph
stopping_dist = stopping_dist + common.meter_per_second(DELTA_TIME * new_velocity)
velocity = new_velocity
iter = iter + 1
total_time += DELTA_TIME
if (iter > 10000):
return -1
if (return_dist):
return stopping_dist
return total_time
def calc_power(total_res, v_bike):
EFFICIENCY = 0.95
return common.meter_per_second(v_bike) * total_res / EFFICIENCY
def calc_air_res(K_A, v_bike, v_wind, alpha_d):
v_bike = common.meter_per_second(v_bike)
v_wind = common.meter_per_second(v_wind)
return calc_wind.get_head_wind2(v_bike, v_wind, alpha_d) * K_A
def dist2(velocity, c_a, c_r):
numer = common.meter_per_second(velocity) * common.meter_per_second(velocity)
denom = 20 * (c_a + c_r)
return numer / denom