Mehedi Hassan

This work demonstrates how to measure jitter using the eye diagram Analyzer histogram feature. Bit sequence generator is employed with the NRZ Pulse generator with the electrical jitter in order to measure the signal amplitude level. We have modulated the light signal from CW Laser with the electrical signal by Mach-Zehnder Modulator through 5 km fiber cables. The signal can be amplified with a gain of 7 dB with the presence of transimpedence amplifier. The combination of electrical signal and signal from noise source can be filtered by using the low pass Gaussian filter.

The effect of tubercles on the leading edge of an airfoil become more vivid at high angle of attacks. The effect of tubercles with large wavelength and small amplitude on the leading edge of a NACA 4412 airfoil section was investigated numerically and experimentally. The phenomena of improving the airfoil performance by modifying the contours drove our interest to do this analysis. The models were developed & numerical simulations were carried out with both NACA 4412 airfoil and modified airfoil model at Re=1.03×10⁶ and angles of attack ranging from 0° to 20°. Flow separation was analyzed with vector profiles. C_L, C_D at different angle of attacks was developed and it gave down noticeable pre-stall & post-stall behavior. The airfoils were studied experimentally in a low speed wind tunnel. Pressure distribution over the two airfoils was obtained. It was evident from the pressure distributions that the modified airfoil exhibits significant aerodynamic performance at high angles of attack. We can infer that these effects will be advantageous for maneuverability and post-stall behavior.