Yash Salgaocar

Hello!

My name is Yash Salgaocar, and I am Master's student at the University of Southern California Majoring in Aerospace Engineering. My particular interests within this field are fluid dynamics, aerodynamics, and thermal systems. In my spare time, I love to cook and learn about food science, jam with my friends on the drums and guitar, and play chess. Please keep reading below to learn more about the projects I have been working on. To learn more about my background and experience, view my resume here.

Computational Fluid Dynamics Study of a Carotid Artery at the Bifurcation

For my final project for a graduate class I took on biofluid dynamics (AME 536), I developed and validated a CFD model with experimental data from an MR Imaging study on velocity profiles in the caroid artery near the bifurcation zone. My simulation models blood as a non-Newtonian fluid, using the Carreau-Yasuda model to estimate viscosity as a function of shear rate. Additionally, this CFD model is time-dependent, with a specified pulsatile velocity for a full cardiac cycle specified from the experimental results at the inlet. The CFD model agreed with the MR Imaging results within reported one standard deviation of the MR Imaging experimental results, which was around 0.085 m/s. To learn more about the CFD model and the MR Imaging study, access my paper here.

I also made qualitative comparisons of the results of the CFD model with flow features at the carotid bifurcation available in literature. This image on the right compares velocity streamlines of the CFD model and those of an ex vivo experimental model that used hydrogen bubble flow visualization in a glass model of a carotid bifurcation. Major flow features like the flow separation at the bulb of the ICA and peak velocities near the inner walls of the ICA and ECA were captured in the model. Additionally, the flow follows the expected Poiseuille flow pattern in the CCA region and also shows the boundary layer effects at the walls of the carotid.

Formula SAE Aerodynamics

Trade Study on Downforce, Drag, and Vehicle Mass

Three key factors to consider when designing an aero package in Formula SAE is downforce, drag, and weight. In order guide design decisions for the aero package, I swept these three parameters in the Optimum Lap simulator to determine their effect on lap times. The plot shows an increase in the aero scaling factor (scaling downforce and drag equally) decreases lap times--designing for maximum downforce outweighs designing for aero efficiency (Lift/Drag). Additionally, a high performing aero package would outweigh a light but poor performing aero package i.e. a 74% increase in aero package weight needs only a 12% increase in the aero scaling factor to produce the same lap time. From these results it was clear that designing and aero package for maximum downforce would result in the most performance gains.

Front Wing Design Changes

The front wing for the SCR19 features several design changes outlined in Figure 2 to improve aerodynamic performance. A thinner, much less cambered mainplane performs much better than high-lift airfoils in ground effect, having less stall characteristics and ride height sensitivity. CFD Simulations in STAR CCM+ at 35 mph with a moving ground plane and rotating tires were used to simulate aerodynamic performance for downforce, drag, and ride height sensitivity shown in in Figures 3, 4, and 5. Additionally, having an adjustable third element shown in Figure 6 allowed for changes to aero-balance from 53% to 47% front bias to tune handling characteristics based on driver preference.

Rear Wing Design Changes

Since the rear wing of the vehicle is not in ground effect, it is much more challenging to find rear downforce. Driver feedback from SCR18 suggested that the vehicle lacked grip in the medium to high speed corners, suggesting a lack of rear downforce. To address this issue, the SCR19 rear wing has two extra elements and a more optimized wing configuration from iterating slot gaps and overlaps of the airfoils shown in Figure 8. The new rear wing produced 42% more downforce compared to the SCR 18 rear wing.

Rear Wheel and Suspension Package