[Remote] Senior Research Engineer, CFD Algorithm Development

Note: The job is a remote job and is open to candidates in USA. SandboxAQ is a high-growth company delivering AI solutions that address some of the world's greatest challenges. The Engineering Team is looking for a Senior Research Engineer, CFD Algorithm Development to develop and deploy a differentiable Computational Fluid Dynamics (CFD) framework on multi-GPU and multi-node systems to optimize chemical reactor designs. Responsibilities • Lead the development of differentiable CFD solvers using JAX for non-isothermal and reactive flow simulations on multi-node, multi-GPU hardware • Optimize reactor scale flow by integrating transport equations for up to 50 chemical species and linking catalyst property predictions with gradient-based optimization • Deliver scalable scientific software that enables physics-based optimization of complex reactor geometries through immersed boundary methods and parallel linear solvers • Develop Differentiable Solvers: Lead the creation of differentiable CFD frameworks in JAX, extending capabilities to complex geometries and non-periodic boundary conditions using immersed boundary methods • Scalable GPU Engineering: Design, implement, and containerize code (Docker/enroot) to ensure reproducibility and scalability across multi-node GPU HPC environments • Numerical Optimization: Develop optimized parallel linear solvers (FFT or matrix decompositions) and gradient-based scripts to iteratively modify reactor designs based on catalyst activity • Validate & Benchmark: Rigorously validate simulation accuracy against benchmark results and fixed-bed reactor configurations for both non-reactive and reactive flow regimes • Cross-Functional Collaboration: Partner with AI model developers to integrate property predictions and generate comprehensive technical reports summarizing algorithm scalability and differentiability Skills • PhD or MS in Computational Physics, Mechanical/Chemical Engineering, Computer Science, or equivalent • 3+ years (including PhD) of hands-on experience in CFD code development, specifically on GPUs • Proven ability to build scalable software on multi-GPU systems using JAX, PyTorch, CUDA, or MPI frameworks • Full fluency in numerical linear algebra, PDE numerical methods, sparse/dense linear solvers, and immersed boundary methods • Excellent Python programming skills, with JAX proficiency as a prerequisite • Ability to manage multiple deliverables and produce clear technical documentation for milestone reviews • PhD + 3 years of industry experience in a related computational field • Proven expertise in non-isothermal flow, transport equations, and chemical reactor multi-physics (e.g., mass transport in fixed-bed systems) • Expertise in adjoint optimization or auto-diff for gradient-based optimization of complex CFD objectives • Experience with the full stack of scientific development, including CI/CD, unit testing, and deployment via K8s, Slurm, or Google Cloud Batch • Demonstrated ability to deliver complex project milestones and publish high-quality technical results Benefits • Comprehensive medical, dental, and vision coverage for employees and dependents with generous employer premium contributions • Retirement savings with company matching • Paid parental leave • Inclusive family-building benefits • Flexible paid time off • Company-wide seasonal breaks • Support for flexible work arrangements that enable sustainable performance • Opportunities for continuous learning and growth through on-the-job development, cross-functional collaboration, and access to internal learning and development programs Company Overview • SandboxAQ develops AI and quantum technology solutions that enhance biopharma, cybersecurity, and materials science. It was founded in 2016, and is headquartered in Palo Alto, California, USA, with a workforce of 51-200 employees. Its website is Company H1B Sponsorship • SandboxAQ has a track record of offering H1B sponsorships, with 7 in 2025, 6 in 2024, 3 in 2023, 5 in 2022, 1 in 2021, 5 in 2020. Please note that this does not guarantee sponsorship for this specific role. Apply tot his job