A new place for utility functions

[giovaniceotto]

@Gui-FernandesBR mentioned some candidates to be included in the utilities.py module being introduced in #108:

Environment.py:
decimalDegressToArcSeconds(self, angle)

Flight.py:
calculateFinFlutterAnalysis(self, finThickness, shearModulus)
exportPressures(self, fileName, timeStep)

These could help give more "body" to this new module.

Also, @Gui-FernandesBR recommends creating a simple example usage for these functions. At least for me, it is not easy to visualize how I could use the new capabilities.

[Lucas-KB]

I do agree with most of what @Gui-FernandesBR and @giovaniceotto suggested, but I am not sure if exportPressures fits here. I believe that one belongs in the Flight class, just like exportEng belongs in the SolidMotor class, does it make sense to you?

I suspect you might have thought of this because exportPressures feels a little weird in the sense that it is special for pressures, because it was created to help the electronics team at Projeto Jupiter. What may be a way around this is to implement a more generic function that exports any number of selected simulation results to a csv file (with all that time step thing that exists in exportPressures). What do you think?

[giovaniceotto]

@Lucas-KB, I completely agree with you.

[Gui-FernandesBR]

@Lucas-KB awesome comment. I think we should go for that, a generic function to export simulations data to .csv files may be very useful. It seems @aipla999 was creating similar things at #62

Just adding an idea: We could have (1) a standard set of data to be exported and also (2) the possibility of customizing what you want to export. What do you think?

[Lucas-KB]

@Gui-FernandesBR I did not know about #62, seems very interesting. Do you have any suggestion on what could be in the standard set of data? I believe the obvious answer would be to output everything, any different ideas?

[Gui-FernandesBR]

Weel I think the u vector would be enough (time, x, y, z, vx, vy, vz, ax, ay, az, etc.)

Just for comparision reasons, OpenRocket currently can export all the following data when requested:

Time (s); Altitude (m); Vertical velocity (m/s); Vertical acceleration (m/s²); Total velocity (m/s); Total acceleration (m/s²);
Position East of launch (m); Position North of launch (m); Lateral distance (m); Lateral direction (°); Lateral velocity (m/s);
Lateral acceleration (m/s²); Latitude (°); Longitude (°); Gravitational acceleration (m/s²); Angle of attack (°); Roll rate (°/s);
Pitch rate (°/s); Yaw rate (°/s); Mass (g); Propellant mass (g); Longitudinal moment of inertia (kg·m²); Rotational moment of inertia (kg·m²); CP location (mm); CG location (mm); Stability margin calibers (?); Mach number (?); Reynolds number (?); Thrust (N); Drag force (N); Drag coefficient (?); Axial drag coefficient (?); Friction drag coefficient (?); Pressure drag coefficient (?); Base drag coefficient (?); Normal force coefficient (?); Pitch moment coefficient (?); Yaw moment coefficient (?); Side force coefficient (?); Roll moment coefficient (?); Roll forcing coefficient (?); Roll damping coefficient (?); Pitch damping coefficient (?); Coriolis acceleration (m/s²); Reference length (mm); Reference area (m²); Vertical orientation (zenith) (°); Lateral orientation (azimuth) (°); Wind velocity (m/s); Air temperature (°C); Air pressure (mbar); Speed of sound (m/s); Simulation time step (s); Computation time (s)

I don't think we need all these data at once, starting with simple ones would be fine for me.
But of course I'm open to suggestions as well.

[Gui-FernandesBR]

Is that possible that the following functions be implemented on utility functions?

• CompareRockets
• ApogeeByMass
• OutOfRailByMass

[lucasfourier]

In my opinion, "CompareRockets" is the perfect candidate and would suit just fine in utilities.py. Regarding the other two, I am not so sure.