章节大纲

    • Inertia force＝ Gravity - Buoyancy - Resistance













    • 10秒程度で等速になる　Constant velocity in about 10 seconds.

    • Equation of motion of an object in fluid


      慣性力　Inertia Force

      重力　Gravity

      浮力　Buoyancy

      抵抗力　Resistance Force

      投影面積　Projected area

      流体の抵抗係数　Resistance coefficient of fluid

      時間　Time

      速度　Velocity

      体積　Volume

      流体の密度　Density of fluid

      粒子の密度　Density of particles

    • Particle motion：Stokes' law

      terminal settling velocity：ut (Terminal Velocity)

      When fine particles are added to a stationary fluid, they initially accelerate, but soon reach a constant velocity. This velocity is the "terminal settling velocity."

      粒子の密度　Density of particles

      流体の密度　Density of fluid

      流体の粘度　Viscosity of fluid


    • Equation of motion for spherical particles in fluid


      慣性力　Inertia Force

      重力　Gravity

      浮力　Buoyancy

      抵抗力　Resistance Force

    • Resistance coefficient and Reynolds number


    • Reynolds number，Re（Indicator of fluid flow condition）


      粒子の直径　Particle diameter

      相対速度　Relative velocity

      流体の密度　Density of fluid

      流体の粘度　Viscosity of fluid

      慣性力　Inertial force

      重力　Gravity

      浮力　Buoyancy

      抵抗力　Resistance force

      終末速度(等速)　Terminal velocity (constant velocity)

    • Stokes' law 


    • We have verified by calculation that it takes about 10 seconds to reach constant velocity.





      体重を70kgとして、投影面積を上記のように仮定すると　Assuming a weight of 70 kg and the projected area as above