Rajesh

Reading data in parallel using MPI I/O

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In the previous post “First steps in parallel file access using MPI I/O“, we discussed how to write some simple data in parallel using MPI I/O. Here we shall read back that data in parallel. The entire code is given in my GitHub repo MPI_Notes. Essentially, we have the following text data in a file: … Read more Reading data in parallel using MPI I/O

First steps in parallel file access using MPI I/O

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If your code uses MPI for parallelization, then you may want to use MPI I/O for writing and reading data from files in parallel. It is common to see the use of POSIX parallel approach where each MPI process reads/writes a separate file. This approach has the following drawbacks: Not efficiently scalable for very high … Read more First steps in parallel file access using MPI I/O

Parallel computing approaches for CFD

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When it comes to parallel computing, there are many ways to solve any complex scientific computing problem. Some are more suitable than others. The method and approach should be determined on a case by case basis with an understanding of the computational algorithm and data structures involved. In this series of articles, I will describe … Read more Parallel computing approaches for CFD

An invitation to fluid dynamics from the oceans

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The last few weeks, I have been engrossed with the oceans and navigation in their vast expanse. It all started with a couple of movies I watched. The first movie “Kon-Tiki” beautifully portrays the 1947 expedition by Norwegian explorer and ethnographer Thor Heyerdahl across the south pacific, from Peru to polynesia. The remarkable thing was that … Read more An invitation to fluid dynamics from the oceans

Fourier transform for confused engineers

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If you are an engineer, you most likely encountered one of the following situations: Plot the power spectral density of a signal you have Find the dominant frequency/mode in a signal A journal paper stating, “It is obvious(?!) that this operation is straightforward to carry out in wave space”. I have been in many such … Read more Fourier transform for confused engineers

Installing HDF5 and CGNS in Ubuntu 18.04 LTS

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If you are a computational fluid dynamics (CFD) practitioner, at some point, you would have to use Hierarchical Data Format 5 (HDF5) and CFD General Notation System (CGNS) libraries in your programs. HDF5 format provides an advanced way of organizing any data and allows efficient access to the data. CGNS prescribes specific methods and practices … Read more Installing HDF5 and CGNS in Ubuntu 18.04 LTS

Numerical Solution of the Falkner – Skan Equation

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Falkner – Skan equation is a third order non-linear ordinary differential equation which arises in the laminar boundary layer flow past wedge-like objects. (More details here). The equation reads, where m is a constant representing the pressure gradient parameter. Our objective is to solve this differential equation for , for a given value of m … Read more Numerical Solution of the Falkner – Skan Equation

Why are sound waves longitudinal?

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“Give me some example for waves in nature! ” “Sound is a wave.. Light is a wave.. Of course we see water waves.. ” Thats the usual answer we think about when asked that question.  Moreover, we are told that sound waves are longitudinal waves (compression waves) and light waves are transverse waves.  But we … Read more Why are sound waves longitudinal?