#!/usr/bin/env python3
"""Fluid Dynamics Demo: Drag, Buoyancy, and Underwater Motion.
This demonstrates the new fluid dynamics capabilities:
- Drag force calculations
- Buoyancy (Archimedes' principle)
- Terminal velocity
- Underwater projectile motion simulation
"""
import asyncio
import math
from chuk_mcp_physics.tools.fluid import (
calculate_drag_force,
calculate_buoyancy,
calculate_terminal_velocity,
simulate_underwater_motion,
)
async def demo_drag_force():
"""Demo: Calculate drag force on a falling ball."""
print("\n" + "=" * 70)
print("DEMO 1: Drag Force on Falling Ball")
print("=" * 70)
# 10cm diameter ball falling at 5 m/s through water
print("\nScenario: 10cm diameter ball falling through water at 5 m/s")
print(" - Ball diameter: 0.1 m")
print(" - Velocity: 5 m/s downward")
print(" - Fluid: Water (density = 1000 kg/m³)")
print(" - Shape: Sphere (Cd = 0.47)")
radius = 0.05 # 5cm radius
cross_sectional_area = math.pi * radius * radius # π*r²
result = await calculate_drag_force(
velocity=[0.0, -5.0, 0.0], # Falling downward
cross_sectional_area=cross_sectional_area,
fluid_density=1000.0, # water
drag_coefficient=0.47, # sphere
)
print(
f"\n Drag force: [{result['drag_force'][0]:.2f}, {result['drag_force'][1]:.2f}, {result['drag_force'][2]:.2f}] N"
)
print(f" Magnitude: {result['magnitude']:.2f} N (upward, opposing motion)")
print(f" Reynolds number: {result['reynolds_number']:.0f} (turbulent flow)")
async def demo_buoyancy():
"""Demo: Check if objects float or sink."""
print("\n" + "=" * 70)
print("DEMO 2: Buoyancy - Will it Float?")
print("=" * 70)
# Test 1: Steel ball
print("\nTest 1: Steel ball (1 kg, 10cm diameter)")
radius = 0.05
volume = (4.0 / 3.0) * math.pi * radius**3 # V = (4/3)πr³
mass = 1.0 # kg
result = await calculate_buoyancy(
volume=volume,
fluid_density=1000.0, # water
)
weight = mass * 9.81 # Weight in Newtons
print(f" Volume: {volume:.6f} m³")
print(f" Weight: {weight:.2f} N")
print(f" Buoyant force: {result['buoyant_force']:.2f} N")
print(f" Displaced water: {result['displaced_mass']:.3f} kg")
if weight > result["buoyant_force"]:
print(" Result: ⬇️ SINKS (weight > buoyancy)")
else:
print(" Result: ⬆️ FLOATS (buoyancy > weight)")
# Test 2: Ping pong ball (hollow, light)
print("\nTest 2: Ping pong ball (2.7g, 4cm diameter)")
radius = 0.02
volume = (4.0 / 3.0) * math.pi * radius**3
mass = 0.0027 # 2.7 grams
result = await calculate_buoyancy(
volume=volume,
fluid_density=1000.0,
)
weight = mass * 9.81
print(f" Volume: {volume:.6f} m³")
print(f" Weight: {weight:.4f} N")
print(f" Buoyant force: {result['buoyant_force']:.2f} N")
if weight < result["buoyant_force"]:
print(" Result: ⬆️ FLOATS (buoyancy > weight)")
else:
print(" Result: ⬇️ SINKS (weight > buoyancy)")
async def demo_terminal_velocity():
"""Demo: Calculate terminal velocity for different scenarios."""
print("\n" + "=" * 70)
print("DEMO 3: Terminal Velocity")
print("=" * 70)
# Scenario 1: Skydiver
print("\nScenario 1: Skydiver (belly-down position)")
print(" - Mass: 70 kg")
print(" - Cross-sectional area: 0.7 m²")
print(" - Drag coefficient: 1.0")
print(" - Fluid: Air (1.225 kg/m³)")
result = await calculate_terminal_velocity(
mass=70.0,
cross_sectional_area=0.7,
fluid_density=1.225, # air
drag_coefficient=1.0,
)
print(
f"\n Terminal velocity: {result['terminal_velocity']:.1f} m/s ({result['terminal_velocity'] * 2.237:.0f} mph)"
)
print(f" Time to 95%: {result['time_to_95_percent']:.1f} seconds")
print(f" Drag force at terminal: {result['drag_force_at_terminal']:.0f} N (equals weight)")
# Scenario 2: Raindrop
print("\nScenario 2: Raindrop (2mm diameter)")
radius = 0.001 # 1mm
mass = 0.0000042 # 4.2 mg
area = math.pi * radius * radius
result = await calculate_terminal_velocity(
mass=mass,
cross_sectional_area=area,
fluid_density=1.225,
drag_coefficient=0.47, # sphere
)
print(f" Terminal velocity: {result['terminal_velocity']:.1f} m/s")
print(f" Time to 95%: {result['time_to_95_percent']:.3f} seconds")
async def demo_underwater_motion():
"""Demo: Simulate underwater projectile with drag and buoyancy."""
print("\n" + "=" * 70)
print("DEMO 4: Underwater Torpedo Launch")
print("=" * 70)
# Torpedo: streamlined, heavy, fast
print("\nScenario: Streamlined torpedo launched underwater")
print(" - Initial velocity: 20 m/s forward")
print(" - Mass: 100 kg")
print(" - Volume: 0.05 m³")
print(" - Cross-sectional area: 0.03 m²")
print(" - Drag coefficient: 0.04 (streamlined)")
print(" - Fluid: Water (1000 kg/m³)")
result = await simulate_underwater_motion(
initial_velocity=[20.0, 0.0, 0.0], # 20 m/s forward
mass=100.0,
volume=0.05,
cross_sectional_area=0.03,
fluid_density=1000.0,
fluid_viscosity=1.002e-3, # water
drag_coefficient=0.04, # streamlined
duration=30.0,
dt=0.01,
)
print("\n Simulation duration: 30 seconds")
print(f" Trajectory points: {len(result['trajectory'])}")
print(
f" Final position: [{result['final_position'][0]:.1f}, {result['final_position'][1]:.1f}, {result['final_position'][2]:.1f}] m"
)
print(
f" Final velocity: [{result['final_velocity'][0]:.1f}, {result['final_velocity'][1]:.1f}, {result['final_velocity'][2]:.1f}] m/s"
)
print(f" Total distance traveled: {result['total_distance']:.1f} m")
print(f" Max depth: {abs(result['max_depth']):.1f} m")
print(f" Settled: {'Yes' if result['settled'] else 'No'}")
# Analyze deceleration
initial_speed = 20.0
final_speed = math.sqrt(
result["final_velocity"][0] ** 2
+ result["final_velocity"][1] ** 2
+ result["final_velocity"][2] ** 2
)
speed_loss_percent = ((initial_speed - final_speed) / initial_speed) * 100
print(f"\n Speed loss due to drag: {speed_loss_percent:.1f}%")
print(f" Initial: {initial_speed:.1f} m/s → Final: {final_speed:.1f} m/s")
async def main():
"""Run all fluid dynamics demos."""
print("=" * 70)
print("FLUID DYNAMICS DEMONSTRATIONS")
print("=" * 70)
print("\nShowcasing new fluid dynamics capabilities:")
print(" - Drag force calculations (quadratic drag)")
print(" - Buoyancy (Archimedes' principle)")
print(" - Terminal velocity (force balance)")
print(" - Underwater motion simulation")
await demo_drag_force()
await demo_buoyancy()
await demo_terminal_velocity()
await demo_underwater_motion()
print("\n" + "=" * 70)
print("✨ FLUID DYNAMICS COMPLETE!")
print("=" * 70)
print("\nNew tools available:")
print(" - calculate_drag_force()")
print(" - calculate_buoyancy()")
print(" - calculate_terminal_velocity()")
print(" - simulate_underwater_motion()")
print("\nThese analytical calculations complement the Rapier rigid-body")
print("simulations for comprehensive physics modeling.")
if __name__ == "__main__":
asyncio.run(main())
