xavierdechamps/nozzle_moc_supersonic

A code based on the Method of Characteristics to solve the supersonic flow inside a nozzle

Nozzle_MOC_supersonic

A code based on the Method of Characteristics to solve the supersonic flow inside a de Laval nozzle.

This Matlab / Octave code solves the flow inside a de Laval nozzle of known shape. The flow is assumed to be steady, two-dimensional, irrotational and supersonic. The methods developed in this project are strongly based on the reference book "Gas Dynamics, Volume II, Multidimensional Flow" by Zucrow Maurice J. and Hoffman Joe D., John Wiley and Sons, 1977.

The main routine is called MOC_2D_steady_irrotational_main.m. It contains all the inputs for the geometry of the nozzle. The geometry of this nozzle contains only the diverging part of the nozzle and a sonic condition is assumed at the throat. The radius of the throat is adapted by the parameter (geom.yt). The downstream region shows first a circular arc of radius (geom.rhod) which extends up to an angle (geom.ta). The diverging section is made of a parabolic curve which extends up to an axial distance (geom.xe) and shows an exit lip angle (geom.te). If (geom.ta) and (geom.te) are equal, then the diverging section is a line.

The initial-value line is chosen as the line where the y-velocity component is equal to zero. This line is discretized by (geom.NI) points and the data is propagated downstream by intersecting left-running and right-running characteristics. The compatibility and characteristic equations are numerically solved by a modified Euler predictor-corrector method to determine the x- and y-velocity components and the location of the new node.

Example of result in the case of a horizontal tangent at the exit lip point

Example of result in the case of conical diverging section

nozzle_moc_supersonic's Issues

Test

Get the solution in the exhaust jet

Apply the free pressure boundary point.
Verify if static pressure at nozzle exit lip point exceeds the stagnation pressure (then expansion wave) or is less than the stagnation pressure (oblique shock wave).

Improve the plotting of the results

Add some patches to visualize the 2D solution inside the nozzle.