CFD Analysis for External Aerodynamics of Truck-Trailer Assembly

Aerodynamic performance plays a critical role in the efficiency and functionality of heavy-duty vehicles. For truck–trailer assemblies, airflow behavior directly impacts fuel consumption, stability, and overall operational cost. Understanding how air moves around these complex structures is essential to optimizing design and unlocking performance gains.

In heavy vehicles, drag is one of the most significant resistive forces encountered during motion. Unlike passenger vehicles, truck–trailers present large bluff bodies with complex geometry, leading to separated flow, turbulent wakes, and pressure differentials that increase aerodynamic resistance. However, evaluating these behaviors on a physical prototype can be costly, time-consuming, or limited in scope. CFD offers a powerful alternative—enabling comprehensive analysis under a wide range of simulated conditions.

At VIAS3D, we leverage advanced Computational Fluid Dynamics (CFD) techniques to analyze and refine the external aerodynamics of ground vehicles. The ability to visualize flow patterns, quantify forces, and assess pressure distributions provides engineers with data-driven insights that inform smarter design decisions.

VIAS3D performed an external aerodynamics study to assess airflow around a truck–trailer assembly for a startup smart RV company, quantify the resulting aerodynamic forces, and identify areas of improvement in the baseline design. We conducted a series of CFD simulations under multiple flow conditions to observe how air interacts with the vehicle surfaces.

Key outcomes of this analysis included determining the drag and side forces acting on the assembly, capturing separation zones, wake regions, and turbulent flow structures, and identifying high- and low-pressure areas affecting performance. By comparing aerodynamic coefficients across different operating conditions, we gained insight into how different scenarios influence vehicle behavior and optimized the design to reduce drag using boat tails and rear fairings to minimize wake formation, along with a rounded front fairing to reduce flow stagnation and delay boundary-layer separation, resulting in improved aerodynamic efficiency and reduced drag.​

About VIAS3D 

VIAS3D engineering and simulation team combines decades of analytical and design experience. They have successfully helped to design various products from many industries for strength, stability, rigidity, and fatigue endurance. Our design and analysis capabilities are accomplished through advanced engineering modeling techniques such as Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), Electromagnetics (EMAG), and other tools. Using these advanced tools, we can capture complex design features and nonlinearities arising from materials, geometry, and surface interactions to simulate designs and predict their response before they are brought in production. 

For more details about our software solutions, training, engineering / PLM services or consulting needs, please email us at achakraborty@vias3D.com, mlakshmiraju@vias3D.com, info@vias3d.com or drop a message on Linkedin to https://www.linkedin.com/in/arinc16/, https://www.linkedin.com/in/murthylakshmiraju/  

Contributors: 

Murthy Lakshmiraju, Ph.D., Engineering Consulting Director at Vias3D 

Dr. Lakshmiraju has over 15 years of advanced use and experience in CFD to solve real-life engineering problems for numerous industries, including appliances, energy, oil and gas, and marine, and chemical processing. He graduated with a Master and PhD in Mechanical Engineering from Tennessee Tech, USA. He has experience in different flow physics, including advanced turbulence modeling, multiphase flow, heat transfer, Dynamic Fluid Body Interaction (DFBI), Fluid-Structure Interaction (FSI), Chimera mesh, Conjugate Heat Transfer (CHT), and reacting flows with combustion and emission modeling. 

Sai Sandeep Pydisetti, Sr. CFD Engineer at VIAS3D

Mr. Pydisetti has industrial experience in CFD modeling and simulations, consulting, and technical support. He has worked on a wide range of applications, including aerodynamics, acoustics, thermal, multiphase, and reacting flow applications. His professional interests involve CFD simulation and analysis of fluid dynamics and heat transfer applications.