Coriolis Drift of Discrete Objects

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SUMMARY

The discussion focuses on calculating the Coriolis Drift of bullets, specifically for discrete objects in free-fall, using two primary equations: X:= T * Range * Sin(Lat) * Omega and Y:= Sin(Dir) * T * Range * Cos(Lat) * Omega. The user seeks to extend these equations to account for elevation changes, allowing for calculations of drift when shooting uphill or downhill. The challenge lies in modifying the existing equations to incorporate elevation while maintaining simplicity for implementation in a Pascal program. The conversation also touches on the potential use of Great Circle/Spherical geometry to redefine the problem.

PREREQUISITES
  • Understanding of basic trigonometry and its application in physics.
  • Familiarity with Pascal programming language for implementing mathematical models.
  • Knowledge of Coriolis effect and its implications in projectile motion.
  • Concepts of Great Circle/Spherical geometry for advanced trajectory calculations.
NEXT STEPS
  • Research modifications to projectile motion equations to include elevation effects.
  • Explore Great Circle calculations and their application in trajectory analysis.
  • Learn about iterative methods for simulating ballistic trajectories in programming.
  • Investigate existing literature on closed-form solutions for Coriolis Drift in various contexts.
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Ballistics engineers, physicists, and programmers interested in modeling projectile motion and understanding the effects of Coriolis Drift on bullets in various shooting scenarios.

Sooty
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I am writing a program aimed at 'gun nuts' designed to display Coriolis Drift of bullets (ie, 'discrete objects in free-fall', and not large fluid masses). Using the 2 equations below, I am able to calculate and display the values of Coriolis Drift (in terms of X & Y (vertical and horizontal)) as seen from a Horizontal Plane on the Earth's surface for all cases of Latitude and Direction, (the second 2 essential input terms).
These are my 2 equations:-

X:= T *Range * Sin(Lat) * Omega

Y:= Sin(Dir) * T * Range * Cos(Lat) * Omega;

Where:-
X = Horizontal Drift
Y = Vertical Drift
T = Time to Target
Range = Distance from gun to Target
Dir = Direction/Azimuth of fire in 'compass degrees' - 0 to 360
Lat = Latitude in degrees - from North (+90degrees) to South(-90degrees)
Omega = a Constant for Earth's Rotational Velocity

Now, I am attempting to extend my Coriolis Drift equations to address the same question for all values of Latitude and Direction beyond a Horizontal Plane (as above), to include Elevation above and below the Horizontal (ie, shooting uphill and downhill, +90deg/-90deg).

In short, what I am looking for is the necessary modifications/additions to the above equations (in a form that can easily be implemented in a Pascal program, hopefully using no more exotic math than basic Trig functions!) necessary to take the 7 terms above, plus:-

Elevation of fire from Vertically Up(+90degs) to Vertically Down(-90degs)

and return X and Y (Horizontal and Vertical relative to the Earth at the point in question) values for Drift, as seen by a viewer looking through a scope mounted on a rifle delivering the shot as described.

Thank you!
 
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I have always tracked trajectories by simulating the motion in very small steps. But those simulations had so much going on during the flight that it was completely different from a ballistic trajectory. I do not know if there are usable closed-form solution for your problem.
 
FactChecker said:
I have always tracked trajectories by simulating the motion in very small steps. But those simulations had so much going on during the flight that it was completely different from a ballistic trajectory. I do not know if there are usable closed-form solution for your problem.

'Very small steps'... yes, an 'iterative approach'... that is how I have done it in terms of getting figures for complete ballistic trajectories... literally 'finite element' calculations, a metre/meter at a time, and it gives excellent results. My current problem is really 'nit-picking on top of what is already close to being nit-picking'... so I may just have to accept that although there must be a solution possible, (hey, it's 'only geometry'!) I'm not going to find it!

Tnx for your input.
 
Reviewing my previous question, I believe I can 're-model' it in a way that is 'mathematically equivalent' and will so will allow me to continue with my project.
It addresses the question in terms of Great Circle/Spherical geometry, which although I can find relevant articles on the internet, they present their maths in ways that are waaay beyond my understanding.
So, instead of referring to anything about Coriolis, consider this:

So. Knowing point A on a sphere,
where the position of A is defined solely by Lat, where Lat = Latitude in degrees (as before)

And point B, whose distance from point A is defined (not by actual distance travelled) by the angle Asector, Where Asector = Angle of the sector of a Great Circle path that runs between them.

Now, the direction of point B relative to point A is Dir, where Dir = Direction/Azimuth in 'compass degrees' - 0 to 360 (as measured at point A) along the Great Circle path.

Questions:-
what is the value of Lat of point B?
what is the value of Dir at point A relative to point B on the great Circle path?
- - -
Hopefully, to clarify, if it's not already clear...
2 points on a Great Circle... Lat and Dir for each, obviously different... for my scenario, the distance between the 2 points is defined by the 'included angle' of the 'earth sector' covered, and not by the distance between them on the Earth's surface...
0
 
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