Amaresh Chukkapalli

Geovisualization

Short Academic Bio

Research Interests

I'm currently looking at being able to study and accurately model pyroclastic density currents using computer simulations. The challenges associated with trying to study these pyroclastic density currents (PDCs) is that it can be difficult to uniformly characterize these currents based on their rheology,surrounding topography, the nature of the eruption, as well as many other case specific factors that can variably change the magnitude and propogation of these currents.

However, since these currents do resemble and follow the rules of fluid/granular flow, it is possible to attempt to account for possibe outcomes, specifically the time and distance of runoff, using the respective mathematical applications. The most noteable solution is the Navier-Stokes equation which is used to describe the motion of viscous fluids. Since the Navier Stokes equation is used as a very fundamental solution, there are a number of complexities and variables associated with pyroclastic density currents that make this problem much more difficult to resolve.

For example, the scaling relationship between deposit volume and runoff time/distance, shown by (Dufek, 2016) is one approach to this problem.

This is a p5 animation showing the effect on bubble size on ascent rate through the magma chamber. The bubbles are made of water, and are approximately 10g in mass. Using this information, we were able to calculate a ascent velocity that is being controlled by the bubble radius. To do this, a few extra variables had to be assumed. In this scenario we assume a magma density of approximately 2600 kg/m3. The viscosity is assumed to be 1000 PaS, and a temperature of 1300 K. In order to calculate the net force acting on this bubble, we have to calculate the 3 different forces (Viscosity/drag force, bouyancy, and gravitational force).

Gravitational force is given as mbubble*g.

Bouyancy force is given as mbubble*g*(magma density/bubble density)

Viscous force is given as 6*pi*radius*viscosity*velocity

In order to solve for velocity we have to input the variables given above and solve using the equation for viscous force. each of these variables can be changed within the script.

The most noteable observation from this animation is that smaller bubbles travel much faster through the conduit. This can be especially important when trying to observe and interpret the volatiles present in a magmatic system

The p5 script for this code can be found here