Sr. CFD Engineer, Powertrain

About Rivian

Rivian is on a mission to keep the world adventurous forever. This goes for the emissions‑free Electric Adventure Vehicles we build, and the curious, courageous souls we seek to attract.

As a company, we constantly challenge what’s possible, never simply accepting what has always been done. We reframe old problems, seek new solutions and operate comfortably in areas that are unknown. Our backgrounds are diverse, but our team shares a love of the outdoors and a desire to protect it for future generations.

• As the senior CFD simulations, you will support design and optimization of lubrication and cooling performance of powertrain Drive Units assemblies including e-motors.
• Build, validate and maintain 3D CFD models (steady state and transient) using industry-standard tools (e.g., Simerics, Star-CCM+ or similar) to predict oil splash, pressure drop, heat transfer, and flow distribution across key systems.
• Build, validate and maintain 1D lubrication models (steady state and transient) using industry-standard tools (e.g., AMESIM, GT Suite, Matlab or similar) to predict spray and splash lubrication, churning losses, aeration effect, pressure drop, heat transfer, and flow distribution across key systems.
• Define boundary conditions, load cases, and duty cycles using vehicle usage profiles and test data to ensure simulations represent real customer usage and worst‑case environmental conditions.
• Translate simulation results into clear design recommendations for component owners (Driveline, powertrain, Motor), including geometry changes, ducting strategies, and shielding/insulation concepts.
• Collaborate with designers and system engineers to balance lubrication, thermal, NVH, durability, and manufacturability requirements in a cross‑functional environment.
• Develop and refine correlation between CFD and physical tests, including defining test plans, instrumentation needs, and success criteria for lubrication and thermal validation at component, system, and vehicle level.
• Support root cause analysis on development and field issues where lubrication and thermal performance are potential contributors; propose data‑driven corrective actions and design updates.
• Help build and standardize CFD methodologies, best practices, and templates (meshing strategies, model reduction approaches, post‑processing standards) to accelerate analysis throughput and improve quality.
• Communicate complex analysis results through concise reports and presentations tailored to design engineers, leadership, and cross‑functional partners.

• B.S. in Mechanical Engineering, Aerospace Engineering, Automotive Engineering, or related field required.
• M.S. or Ph.D. with a focus in fluid mechanics, heat transfer, or CFD strongly.
• Minimum 5 years of relevant experience in CFD and 1D thermal analysis for automotive, aerospace, energy, or similar industries (advanced degrees may count toward experience).
• Proven expertise in 1D and CFD pre-processing, solving, and post-processing (Simerics, Star-CCM+ or equivalent).
• Working experience with Simerics-MP+ for rotating machine and gearbox oil splash simulation is a plus.
• Strong foundation in multiphase turbulence physics, fluid dynamics and heat transfer (VOF, surface tension, aeration, conduction, convection, radiation, conjugate heat transfer and turbulence model) with deep understanding in tribology.
• Proficiency in handling complex moving geometries using sliding mesh, overset mesh or morphing techniques for rotating gears, bearings and shafts.
• Strong foundation in fluid dynamics and heat transfer (convection, radiation, conjugate heat transfer, pressure loss, turbulence modeling).
• Experience with Drive Unit or system-level simulations (Full Drive Unit/Transmission flow, thermal management or similar).
• Familiarity with duty cycles and durability concepts (e.g., Oil pump and thermal cycling, life prediction based on SN or temperature-time exposure is a plus).
• Working knowledge of parametric CAD tools and geometry handling (CATIA or similar) sufficient to prepare CFD-ready models and influence design.
• Experience scripting in Python, MATLAB, or similar for process automation, data…