Shobdo: A Two-Fluid Hydrodynamical Code

Wave diagram of shock tube problem. Vertical and horizontal axes display time and distance. The coloured palette displays density. Figure highlights the five distinct states of Riemann's problem. This simulation has been done using SHOBDO.

Shobdo is a two-fluid hydrodynamical code. It uses finite volume method and performs simulation in Eulerian grid. 'Shodbo' is a Bengali word which means sound. Since any fluid code deals with sound speed, this name 'Shobdo' has been given.

Shobdo has various modules such as thermal conduction, radiative cooling, photoionization heating, Cosmic ray diffusion, and CR heating. The current version of Shobdo supports one dimension and Cartesian/Spherical geometry. The user's manual of this code will be provided soon. To see some problems, click on "TestProblems".

Shobdo was mainly developed for this work - Gupta et al. (2018) MNRAS, 473, 1537; [NASA/ADS]; MNRAS; arXiv

A. Advection

A.1. A one dimensional profile that contains a gaussian function and a step function, which are forced to advect with constant speed. The advection speed is set to 1 and boundaries are periodic. Profiles at various time shown below.

B. One-fluid Hydrodynamics

B.1. Cartesian Geometry: Shocktube problem. The initial condition and the animated output are displayed below.

B.2. Spherical geometry: Blastwave. Initial density and temperature of an ambient medium are set to uniform except at the center. In the central region, a high-pressure zone has been set which mimics the supernova explosion at t = 0.

B.3. Critical test problem for checking shock capturing scheme.

This link is under construction.

This code is written by Siddhartha Gupta, a PhD student at Indian Institute of Science and Raman Research Institute, Bangalore India. Click here to see his personal page.

Acknowledgement

SG acknowledges Prasun Dhang and Prakriti Pal Choudhury because they together had started to learn numerical techniques for solving advection equation, which highly motivated SG to write this code. SG thanks Prateek Sharma for debugging many problems and also for suggesting valuable references. SG thanks Biman Nath for encouraging him to add various modules. Without their help, it was impossible to develop SHOBDO.