BUG: Overfilled Tanks produce absurd calculations without an error thrown about rocketpy

[phmbressan]

Thank you for reporting this Bug and creating an issue.

This was already detected and is being fixed by the hotfix PR #479 . A release containing this hotfix will be released in a few days.

Additionally, could you provide more information about which Tank class produced this issue (or even a code sample) so we can check if the planned hotfix covers this case?

[theDiego21]

The Tank used was a MassFlowRateBasedTank.
Here is the code sample, which caused the bug:

Define fluids

oxidizer_liq = Fluid(name="LOX", density=1141)
fuel_liq = Fluid(name="ethanol", density=789)
pressurant_gas = Fluid(name="N2", density=1.034)

Define tanks geometry

eth_tank_shape = CylindricalTank(radius = 13 / 100, height = 0.345409407550068, spherical_caps = True)
lox_tank_shape = CylindricalTank(radius = 13 / 100, height = 0.28827610851596, spherical_caps = True)
pressurant_tank_shape = CylindricalTank(radius = 6 / 100, height = 0.22, spherical_caps = True)

Define tanks

oxidizer_tank = MassFlowRateBasedTank(
name="oxidizer tank",
geometry=eth_tank_shape,
flux_time=5,
initial_liquid_mass=4.695,
initial_gas_mass=0,#.1880196263187668,
liquid_mass_flow_rate_in=0,
liquid_mass_flow_rate_out=lambda t: 0.4815384615384616, #/ 3 * exp(-0.25 * t),
gas_mass_flow_rate_in=0,
gas_mass_flow_rate_out=0,
liquid=oxidizer_liq,
gas=pressurant_gas,
)

fuel_tank = MassFlowRateBasedTank(
name="fuel tank",
geometry=lox_tank_shape,
flux_time=5,
initial_liquid_mass=3.611538461538462,
initial_gas_mass=0,#.1880196263187668,
liquid_mass_flow_rate_in=0,
liquid_mass_flow_rate_out=lambda t: 0.626, #/ 3 * exp(-0.25 * t),
gas_mass_flow_rate_in=0,
gas_mass_flow_rate_out=0,
liquid=fuel_liq,
gas=pressurant_gas,
)

pressurant_tank = MassFlowRateBasedTank(
name="pressurant tank",
geometry=pressurant_tank_shape,
flux_time=5,
initial_liquid_mass=0,
initial_gas_mass=0.1980196263187668,
liquid_mass_flow_rate_in=0,
liquid_mass_flow_rate_out=0,
gas_mass_flow_rate_in=0,
gas_mass_flow_rate_out=lambda t: 2.397258605729897/63,
liquid=fuel_liq,
gas=pressurant_gas,
)

example_liquid = LiquidMotor(
thrust_source=lambda t: 2000,# - 100 * t**2,
dry_mass=2,
dry_inertia=(0.125, 0.125, 0.002),
nozzle_radius=13 / 100,
center_of_dry_mass_position=0.7,
nozzle_position=0,
burn_time=5,
coordinate_system_orientation="nozzle_to_combustion_chamber",
)
example_liquid.add_tank(tank=oxidizer_tank, position=1.5)
example_liquid.add_tank(tank=fuel_tank, position=0.8)
example_liquid.add_tank(tank=pressurant_tank, position=1.1)
example_liquid.add_tank(tank=pressurant_tank, position=1.8)

example_liquid.draw()
example_liquid.info();

By adding the Motor to the Rocket using:
hedy.add_motor(example_liquid, position=-1.255)

The following output is produced, when hedy.draw() is called:

The Method hedy.info(); returns the following:
Inertia Details

Rocket Mass: 25.000 kg (without motor)
Rocket Dry Mass: 27.000 kg (with unloaded motor)
Rocket Loaded Mass: 35.703 kg (with loaded motor)
Rocket Inertia (with unloaded motor) 11: 7.016 kgm2
Rocket Inertia (with unloaded motor) 22: 7.016 kgm2
Rocket Inertia (with unloaded motor) 33: 0.036 kgm2
Rocket Inertia (with unloaded motor) 12: 0.000 kgm2
Rocket Inertia (with unloaded motor) 13: 0.000 kgm2
Rocket Inertia (with unloaded motor) 23: 0.000 kgm2

Geometrical Parameters

Rocket Maximum Radius: 0.13 m
Rocket Frontal Area: 0.053093 m2

Rocket Distances
Rocket Center of Dry Mass - Center of Mass without Motor: 0.041 m
Rocket Center of Dry Mass - Nozzle Exit: 1.214 m
Rocket Center of Dry Mass - Center of Propellant Mass: 8125060076944.635 m
Rocket Center of Mass - Rocket Loaded Center of Mass: 1980500324599.361 m

Aerodynamics Lift Coefficient Derivatives

Nose Cone Lift Coefficient Derivative: 2.000/rad
Fins Lift Coefficient Derivative: 11.071/rad
Tail Lift Coefficient Derivative: -0.490/rad

Center of Pressure

Nose Cone Center of Pressure position: 2.799 m
Fins Center of Pressure position: -0.906 m
Tail Center of Pressure position: -1.224 m

Stability

Center of Mass position (time=0): -1980500324599.402 m
Initial Static Margin (mach=0, time=0): -7617308940765.757 c
Final Static Margin (mach=0, time=burn_out): -9130882444823.043 c
Rocket Center of Mass (time=0) - Center of Pressure (mach=0): 1980500324599.097 m

Parachute Details

Parachute Main with a cd_s of 10.0000 m2
Ejection signal trigger: 800 m (AGL)
Ejection system refresh rate: 105.000 Hz
Time between ejection signal is triggered and the parachute is fully opened: 1.5 s

Parachute Details

Parachute Drogue with a cd_s of 1.0000 m2
Ejection signal trigger: At Apogee
Ejection system refresh rate: 105.000 Hz
Time between ejection signal is triggered and the parachute is fully opened: 1.5 s

[Gui-FernandesBR]

@theDiego21 , I think your error no longer persists on the latest rocketpy. Can you try running pip install rocketpy --upgrade and test your code again please?

[Gui-FernandesBR]

Just tested the same code sample again with latest version 1.1.3 and this is the new output:

I believe this solves the issue