  Simulating the detailed movement of a rising bubble can be challenging,
especially when it comes to bubble path instabilities. Free rising ellipsoidal
bubbles not only move in straight lines but can describe sinusoidal, zigzag or
spiraling paths. The common Euler Euler (EE) simulation techniques can no
longer resolve the actual movement patterns and Direct Numerical Simulations
(DNS) tend to be very costly when simulating a larger number of bubbles. A
solution based on the Euler Lagrange (EL) approach is presented, where the
bubbles show oscillating shape and/or instable paths while computational cost
are at a far lower level than in DNS. The model calculates direction, shape and
rotation of the bubbles to finally create typical instable path lines. This is
embedded in an EL simulation, which can resolve bubble size distribution, mass
transfer and chemical reactions. To ensure realistic solution, validation
against experimental data of single rising bubbles and bubble swarms are
presented. References with 2D and also 3D analysis are taken into account to
compare simulative data in terms of typical geometrical parameters and average
field values.
