3. INTRODUCTION1) The Bathtub Myth2) The goal of this presentation is to account for the factors that determine the vortex rotation direction3) Theoretical Background • The concept of rotational relative movement • The Coriolis Effect
4. Rotational relative movement Velocity & acceleration for P • V= V’ + wxr • a = a’ + 2wxV’ + (wxwxr) The Coriolis Effect The Centrifugal Force can will always be easily be calculated for any perpendicular to the given point, it is maximum object’s velocity. It is on the Earth’s Equator of the order of (0,033 (m/s-2)) and magnitude of accounts for only 0,3% of 0,00014·V’ (m/s-2). gravity’s pull.
5. The Coriolis Effect Because of the Earth’s rotation, we are all moving with angular velocity relative to a static frame of reference. Hence, the Coriolis and Centrifugal accelerations are introduced.(Intuitive explanation) The mathematical expression for the Coriolis Force appeared in an 1835 paper by French scientist Gustave Coriolis.
6. The Coriolis Effect (N.H.) (- π/2 ≤ α ≤π/2) Also due to the cross product, objectsIn free fall, objects always tend to travelling on the Earth’s plane will veerveer to the East (one can check this to the right on the Northernby doing the cross product). Hemisphere, and to the left on the Southern Hemisphere.
7. Bathtub Vortex MythSo when does the Coriolis Effect intervene?• First considered by Riccioli in 1651 for the deflection of canon balls• In the formation of tornados• In the trajectory of missiles• In other phenomena with high Rossby numbersDebunking the myth• The importance of the Coriolis Effect is determined by the Rossby number R(L,V,w)• Residual disturbance, shape of bathtub, and other factors are much more important• Experiment
8. CONCLUSIONS• The Coriolis Effect on Earth is negligible when dealing with low speed and distance.• One must always be skeptic when dealing with popular belief!
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