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Aerodynamic Efficiency of a Semi-Trailer Truck

During my spring 2018 semester at Rowan University, a fellow mechanical engineering student and I were tasked with creating a project of our choice involving some kind of fluid flow analysis for Thermal-Fluid Sciences II. As such, we decided to do a theoretical investigation of the aerodynamic efficiency of a typical semi-trailer truck as compared to one retrofitted with more aerodynamic features.

Results

After performing many different flow simulations on both truck variants at speeds ranging from 25-85mph, we experimentally determine the relationship between speed vs drag, computed the truck's coefficient of drag at various speeds, and calculated that by using our “aero” truck as opposed to a stock truck for commercial purposes, one can save $6,098 on fuel costs annually assuming a distance driven of 45,000 miles.

Challenges

As you might suspect, one of the most challenging aspects of this project was finding the time to run a sufficient number of flow simulations to provide the data necessary to compare our modified truck with the regular variant.

Results

Comparison of Aerodynamic Semi-Truck and a Traditional Semi-Track Traveling at 55mph

Drag Coefficient v.s. Reynolds Number

Drag Coefficient v.s. Semi-Truck Velocity

Semi-Truck Aerodynamic Horsepower Requirement v.s. Semi-Truck Velocity

CAD

Aerodynamic Truck

Aerodynamic Truck - Isometric View, Front

Aerodynamic Truck - Isometric View, Back

Aerodynamic Truck - Side View

Aerodynamic Truck - Top View

Stock Truck

Stock Truck - Isometric View, Front

Stock Truck - Isometric View, Back

Stock Truck - Side View

Stock Truck - Top View

Flow Simulation Comparison

Pressure Cut Plot - Side View

Stock Truck: Stock Truck Pressure Cut Plot - Side View

Aerodynamic Truck: Aerodynamic Truck Pressure Cut Plot - Side View

Flow Velocity Cut Plot - Side View

Stock Truck: Stock Truck Flow Velocity Cut Plot - Side View

Aerodynamic Truck: Aerodynamic Truck Flow Velocity Cut Plot - Side View

Flow Trajectory - Front View

Stock Truck: Stock Truck Flow Trajectory - Front View

Aerodynamic Truck: Aerodynamic Truck Flow Trajectory - Front View