The Preliminaries

In December 2006, I attended a week long symposium on Fluid Mechanics and Energy transfer at Digha (West Bengal, India), where I met Prof. Franz Durst, a German professor of Fluid Mechanics.
We talked (briefly) about Fluid Mechanics, the Navier-Stokes Equations, and conflict between the practices of theoretical modeling and actual verification.

About two months later, in February 2007, Prof. Durst wrote to me asking if I would like to carry out an internship under him at a German company called Promeos. I was fairly unsure at the time about whether I could manage an internship and survive at a (back then) seemingly alien city. More importantly, I had already secured a summer internship at the Indian Institute of Science under Prof. J. Srinivasan- both projects seemed equally intriguing, and I was equally eager to work under either of the professors. (Both of them are behemoths in their fields, and very experienced people- It is hard to explain how delighted I was at the prospect of learning from them, and how hard the choice was)

At Germany, I was expected to work on porous combustion technology, which is a process of burning fuel without allowing it to form a flame. (For various reasons, a few of which I now realize, this is better than normal combustion) This would involve using basic momentum and energy transfer equations to model heat transfer in porous materials- fundamental (and hence fascinating) stuff.
At IISc, I was expected to handle climate modeling, which would involve a lot of thermodynamics (always a plus where I'm concerned) and fluid mechanics. I will leave out the details, because I am not entirely sure of them- but rest assured that this seemed at the time to be an equally fascinating field.

I did what I could- I talked to people I whose opinions I thought sensible, and whose advice I value (this is a very short list!), and made a list of pros and cons of either choice.

As an example, some pros on the German Internship scenario were
(i) Basic Fluid Mechanics and Heat Transfer
(ii)Working under Prof. Durst,
(iii)Insight into the way German companies work, etc.

The cons included
(i)Virtually no vegetarian food
(ii)Looong distance travel (and its associated hassles) involved
(iii)Zero knowledge of German,
(iv)No local cure for homesickness available, etc.

To save myself from the mental anguish of having to choose, I let a coin make the decision for me. Heads it was, and I boarded the flight to Frankfurt on 15th May, 2007. (This was preceded by considerable anxiousness and finger-crossing as the visa issues were being sorted out, but with help from the 42nd, uncle RC, home, and Prof. JS, this was sorted out- no reason to explain that in here.)