Shallow water Analysis
To analyze the air flow around our experiment at supersonic speeds we have performed a shallow water analysis.
The shallow-water analysis implies that a compressible flow (1D and 2D) and a fluid flow with free surface and low depths can be described under certain conditions by the same equations. Hence by observing the valleys and hills upon the water we can get a rough estimation of the pressure and speed distribution.
For a better knowledge of fluid flow around our experiment, we used the shallow water method to analyze these using the facilities of the chair of fluid mechanics at TU Dresden. With these results we can simulate the flight of the rocket in a simple way.
For the shallow water tests, a simplified 1:1 model of the available rocket and a 5:1 model of the cavity were built. The test speed range could be taken from the records of a previous flight of REXUS.
Initial experiments contained the introduction into the test bed and the handling as well as gather the first impressions of the generating fluid flow above the simplified model of the rocket. At the same time, water levels were taken at the rocket contour to calculate the flow velocity.
The objective of the shallow water test at different speeds was the detection of air exchange in the cavity. Therefore the model of the cavity was flowed round at velocity rates of Fr = 1.5 – 3.2. Where the Froude number [Fr] is the equivalent to the Mach number [Ma]. At the different upstream velocities, the streamlines along the contour and the measurement range were visualized with colored liquid.
Testing the electronic systems
Our electronic test system is based on OLIMEX P103 boards with a Cortex M3 on it. It is very important to test library and find errors and to fix them.
Testing included nearly all interface Protocols that we want to use to.
Following Protocols are supported by our Software:
I2C
SPI
RS232 and RS485
