[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. They are seeking a hands-on computational scientist or engineer to lead the CFD Algorithm Development Project, focusing on developing and deploying a differentiable Computational Fluid Dynamics framework to optimize chemical reactor designs. Responsibilities• Lead development of differentiable CFD solvers for non-isothermal and reactive flow simulations on mulit-node multi-GPU hardware using JAX• Design, implement, and containerize code to ensure reproducibility, scalability, and ease of deployment across HPC GPU environments.• Develop optimized parallel linear solvers using FFT or other matrix decompositions• Extend existing implementation of immersed boundary method to complex geometries and non-periodic boundary conditions• Extend and validate CFD capabilities from single-node to multi-node GPU systems for both non-reactive and reactive flow regimes. • Integrate transport equations for up to 50 chemical species using linear numerical methods. • Validate simulation accuracy against benchmark results and fixed-bed reactor configurations.• Develop gradient-based optimization scripts to iteratively modify reactor designs based on objective functions defined by catalyst activity and selectivity. • Collaborate closely with AI model developers to link catalyst property predictions with reactor-scale flow optimization. • Generate comprehensive technical reports summarizing algorithms, scalability, differentiability, and validation results for milestone reviews. Skills• PhD or MS in Computation Physics, Mechanical or Chemical Engineering, Computer Science or equivalent discipline.• 3+ years (including PhD) of hands-on experience in CFD code development, preferably on GPUs• Proven expertise building scalable scientific software on multi-GPU systems using JAX, PyTorch, CUDA, MPI frameworks or similar. • Full fluency across all of: numerical linear algebra, numerical methods for solving PDEs, sparse and dense linear solvers, immersed boundary methods• Excellent Python programming skills, with experience in JAX a prerequisite• Ability to work independently, manage multiple deliverables, and produce clear technical documentation.• PhD + 3 years industry experience in Computational Physics, Mechanical/Chemical Engineering, Computer Science or related field• Proven expertise in CFD code development for non-isothermal flow, transport equations, and reactive flow modeling. • Proven expertise with differentiable computational fluid dynamics, and/or gradient-based optimization of complex CFD objectives (i.e. adjoint optimization, auto-diff a.s.o)• Proven experience across the full stack of scientific software development including PR submission, code review, unit-testing, integration testing, containerization with Docker and enroot,, and deployment on GPU-HPC systems using k8s, bolthires Cloud Batch, slurm or similar.• Proven expertise in chemical reactor and multi-physics modeling (e.g., reactive flow, energy and mass transport in fixed-bed or catalytic systems). • Demonstrated track record of delivering project milestones and publishing high-quality technical results. Benefits• Annual discretionary bonuses• EquityCompany 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 isCompany H1B Sponsorship• SandboxAQ has a track record of offering H1B sponsorships, with 6 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