Dr James Sprittles

University of Warwick

My research has been mainly on the the mathematical modelling and computational simulation of technologically-relevant capillary phenomena, many from a class of 'singular flows'.

I have focussed on flows with complex interfacial effects, which are particularly relevant in the emerging fields of nano- and microfluidics, where surface forces control a liquid's flow characteristics.

Experimental analysis of such phenomena are complex due to the small spatio-temporal scales of interest so that mathematical modelling and simulation are invaluable tools with which to understand such flows.

More information about my research can be found on my webpage: http://homepages.warwick.ac.uk/staff/J.E.Sprittles/.

Some simulations from this work can be found on my YouTube Channel.

 

Biography

I am an Assistant Professor in the Mathematics Institute at the University of Warwick.

My undergraduate and postgraduate education was at the University of Birmingham, culminating in a PhD in Applied Mathematics on the topic of dynamic wetting, supervised by Professor Yulii Shikhmurzaev.  I then won an EPSRC Postdoctoral Fellowship in Mathematics to work on flow through porous media after which I moved to Oxford as a Junior Research Fellow in the Oxford Centre for Collaborative Applied Mathematics.  In 2013 I moved to Warwick as a Global Research Fellow in the Institute of Advanced Study before being appointed to a permanent post in 2016.

SWEP Workshop, Brighton

On May 17/18 Rohit and I gave invited talks at the inaugural Surface Wettability Effects on Phase Change Phenomena (SWEP) workshop in Brighton.  This was organised by Joel De Coninck, our first Visiting Scientist of the Programme, and Marco Marengo who are both experts in this field - their hope is that this workshop will become a yearly fixture.  They opened the workshop by reminding the audience of the incredible effects that wettability can have: adding just one layer of molecules to the top of a surface can completely change the shape of mm-sized drops that sit on top of them, which is the equivalent in scale of ants being able to change the shape of mountains (apologies for the poor quality photo)!

Rohit and I gave the last and first talks, respectively, with Rohit impressing the audience with his work on acoustofluidics whilst I spoke about 3 canonical problems involving kinetic effects in interfacial flows, including work with Mykyta (drop impact), Anirudh (drop evaporation) and Duncan.

There were many interesting presentations on a wide range of phase change phenomena.  I particularly enjoyed Carlo Antonini's talk "License to Freeze" which reviewed methods for controlling ice formation on surfaces (including an inverse Leidenfrost effect, where evaporation occurs from the underlying substrate rather than the impacting drop drop, which we could potentially simulate) and Daniel Attinger's talk on "What is the Optimum Wettability of a Pool Boiling Heater?", which carefully explained the experimental and theoretical challenges of understanding the subtle interplay between wettability, phase change and heat transfer driven by bubble formation at a (complex) solid surface.

All in all the workshop was very enjoyable and the level of scientific discussion was high (i.e. Rohit and I got grilled!) - I would recommend it to our group members in future years.

Welcome to Vinay!

Warwick welcomes Vinay Gupta who has started a 2-year Commonwealth Rutherford Fellowship in the Mathematics Institute.  Vinay's background is in exploiting moment methods to describe gas mixtures and granular gases.

Warwick welcomes Shiwani

Dr Shiwani Singh has joined the Micro and Nano Flows team at Warwick, where she will be based in the Maths Institute.  She will be looking into multiscale modelling of viscoelastic flows over the next couple of years.

Magic (?) Ball

A few nights ago Ernest (my two year old son) and I made a discovery that could have potentially revolutionary impact on the field of fluid dynamics; at bath time.  One of his balls had wandered under the running tap... and, as if by magic, got stuck there!

"Wow, that's incredible, why doesn't the jet push the ball away?", I hear you all cry.  "What black magic is at play in your bath? Where is the invisible string?"

Our initial thought was that this looks like the reverse of the well-known effect where a air jet can stably levitate a ball (e.g. a hair dryer levitating a table tennis ball or, for Ernest, the airjet in the ballpit at softplay).  This is all due to the Bernoulli effect - the suspended ball remains stable as a small deviation to one side slows the stream on that side, increases the pressure there and hence restores the ball back to the centre.

But then we found a YouTube video:

Which says it's not the same effect when a ball is levitated by a water jet.  But our ball doesn't seem to spin as violently as theirs, but rather bobs from side to side.

So now we're confused again.

 

 

Dr Anirudh Singh Rana wins prestigious Marie Skłodowska Curie Fellowship at Warwick

Congratulation to Anirudh who has won a highly competitive two-year fellowship at the Institute of Advanced Study in Warwick through their WIRL-COFUND scheme. Anirudh will continue to work in our Group but will also be driving his research in new exciting directions which he proposed for this fellowship.

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