Recently, ISRO has developed a Parallel RANS Solver for Aerospace Vehicle Aero-thermo-dynamic Analysis (PraVaHa), Computational Fluid Dynamics (CFD) software.

About PraVaHa Software 

  • This software was developed in ISRO’s Vikram Sarabhai Space Centre (VSSC).
  • It can simulate external and internal flows on launch vehicles, and winged and non-winged re-entry vehicles.
  • Any aerospace vehicle while moving through the Earth’s atmosphere during launch or re-entry is subjected to severe aerodynamic and aerothermal loads in terms of external pressure and heat flux.
  • Understanding the airflow around aircraft, rocket bodies, or Crew Module (CM) during earth re-entry is essential to design the shape, structure, and Thermal Protection System (TPS) required for these bodies.
  • PraVaHa has been used extensively in the Gaganyaan program for aerodynamic analysis of human-rated launch vehicles, viz, HLVM3, Crew Escape System (CES), and CM.
  • Currently, the PraVaHa code is operational to simulate airflow for Perfect Gas & Real Gas conditions.
  • Validations are ongoing for simulating the effects of chemical reactions during air dissociation upon earth re-entry and combustion in scramjet vehicles.

Computational Fluid Dynamics (CFD)

  • It is one such tool to predict the aerodynamic and aerothermal loads which solve numerically the equations of conservation of mass, momentum, and energy along with the equation of state.
  • Presently, CFD is mature enough in terms of its accurate prediction capability for complex aerodynamic flows, as well as faster simulation turnaround time on High-Performance Computing Clusters.


  • PraVaHa is expected to replace most of the CFD simulations for aero characterisation, which is currently being carried out using commercial software. 
  • This software is expected to help academia and other institutions, engaged in the design of missiles, aircraft, and rockets, to find solutions to complex aerodynamic problems.

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