 I am Samina, I will be offering this course on gas dynamics. Typically a fluid flow is classified as incompressible flow or compressible flow. If the rate of change of density due to pressure is negligible or very small, it is called incompressible flow otherwise it is compressible flow. In this course we are going to deal with compressible flows which are called gas dynamics. These kinds of flows are typically encountered in high speed aerodynamics such as rockets and supersonic jets or in astrophysical fluids. We are going to deal with gases and we are going to study the constitutive equations fundamental physics of such flows. The first few classes we will deal with thermodynamics which is actually a prerequisite for the course. Then we go into the isentropic flows, the concept of isentropic flows. We also introduce how to use gas tables. We typically deal with flows with gas properties of ratios of specific heats 1.4. In fact that is the only gas kind of gas we are going to deal in this particular course. Then we go on to describe, try to understand flows with shocks and expansion fans and other things. So that is essentially about the course and the details are given in the home page of NPTEL. We will have at least 10 assignments for this course of which we will try to take 6 best assignments for the grading. 40% of the entire the course evaluation is based on the assignments and 60% is for the return exam that is going to happen sometime in April or May as given in the website of NPTEL. I will be assisted by 2TS Ashodinayar and Manjul Sharma. So we will be happy to take any questions in the forum that is again given in the NPTEL websites. Thank you and welcome to the course.