Simulation Engineer (CFD) - Large Physics Models

PhysicsX; City Of London; Hybrid; GBP 55,000 - 90,000; Full time

Benefits offered by this job

Equity options

Pension 10%

Free lunches

Enhanced parental leave

Nursery scheme

25 days Annual Leave

Private medical insurance

Wellhub subscription

Eye tests

Personal development

EAP

Job summary

PhysicsX Ltd. is seeking a Simulation Engineer to help build the data generation foundation for Large Physics Models.

You will generate simulation data, develop numerical solvers, and work with ML researchers to bridge physics and model development. The role blends CFD with differentiable and GPU-native approaches, balancing fidelity and cost in a research setting.

Based in London, this hybrid role combines office days with flexible remote work and collaboration across industrial partners.

Qualifications

• Postgraduate degree in engineering, applied mathematics, physics or related field; PhD preferred but not essential.
• 1–2 years of industry CFD experience in relevant sectors (aerospace, defence, CPI, turbomachinery).
• Experience developing numerical solvers or PDE solvers in JAX, Warp or similar frameworks.
• Hands-on with at least one commercial CFD solver (STAR-CCM+ or Fluent).
• Comfort working in a research environment with open-ended problems.

Responsibilities

• Generate simulation data for training large-scale ML models with varied fidelity.
• Develop and implement solvers and numerical methods in modern frameworks (e.g., differentiable or GPU-native).
• Work with multi-fidelity data, balancing fidelity with CFD simulators.
• Produce reference data using commercial and open-source CFD tools.
• Collaborate with ML researchers to translate physics into models and improve data quality.
• Shape the data generation direction and highlight where simulation investments unlock progress.

Skills

CFD experience

Solvers development

Research collaboration

Python/JAX experience

Education

MSc or PhD in engineering / applied math / physics

Tools

Simcenter STAR-CCM+

Ansys Fluent

JAX

NVIDIA Warp

Job description

About Us

Re-architecting Engineering for the Age of Intelligence

PhysicsX is the physics AI company for industrials. The company’s mission is to accelerate hardware innovation by overhauling what industrial engineering and manufacturing look like today. PhysicsX is building a new simulation software stack to deliver deep physics AI enablement across the entire engineering lifecycle. The company partners with leading organisations in aerospace & defence, automotive, semiconductors, materials, and energy & renewables, supporting them on some of their most critical and complex challenges. PhysicsX is headquartered in the United Kingdom, with offices in London, New York, and Singapore and an expanding presence in the Bay Area.

About The Role

Large Physics Models need data, and the quality, diversity and cost of that data shape is what we need to define. As a Simulation Engineer in our Research team, you will build the simulation side of that foundation. You’ll work in a research environment, alongside ML researchers and engineers, on how physics-based simulation and machine learning can be combined in ways that haven’t been done before. You’ll be working at the frontier of Large Physics Model development, shaping new AI paradigms for our customers to benefit from in the future. You will aid in data generation, how, and at what fidelity, so that the models we build are both accurate and affordable to train.

What you will do

• Generate simulation data for training large-scale ML models, drawing on a mix of methods and fidelity levels.
• Develop and implement solvers and numerical methods, potentially in modern differentiable or GPU-native frameworks such as JAX or NVIDIA Warp.
• Work with multi-fidelity data: understand tradeoff between fidelity and CFD simulators and how the two can be combined.
• Use commercial and open-source CFD tools to produce reference data
• Collaborate closely with ML researchers and engineers, translating between the physics and the models, and helping the team get the best corpus possible.
• Contribute to the technical direction of our data generation work and flag the simulation investments that will unlock research progress.

What you bring

• A postgraduate degree (MSc or PhD) in engineering, applied mathematics, physics or a related field, ideally with research involving numerical analysis of PDEs or computational engineering. A PhD is preferred but not required.
• At least 1-2 years of industry experience in CFD, ideally in turbomachinery, aerospace, defence or the chemical and process industries (CPI).
• Experience developing numerical solvers or PDE solvers, for example in JAX, Warp or a comparable framework.
• Hands‑on experience with at least one commercial CFD solver, such as Simcenter STAR-CCM+ or Ansys Fluent.
• Comfort working in a research setting, where problems are open-ended and the path isn’t always clear.

Strongly preferred

• Practical experience with OpenFOAM.
• Exposure to ML or surrogate model development, or experience working directly with ML teams.

Why join us

• Work at the frontier of Large Physics Models, in a team where simulation expertise shapes the research direction.
• Join a research environment with real access to ML talent and compute.
• Influence how we think about data, fidelity and physics in AI.

Please note, this role is based in London, working 2-3 days per week in our central office.

What We Offer

Build what actually matters

Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind.

Learn alongside exceptional people

Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home.

Influence over hierarchy

We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected.

Sustainable pace, long-term ambition

Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our Shoreditch office with work‑from‑home days, giving you the flexibility to work sustainably while staying connected in person.

And it doesn’t stop there …

• Equity options - share meaningfully in the company you’re helping to build.
• 10% employer pension contribution - because investing in future matters.
• Free office lunches - to keep you energised and focused.
• Enhanced parental leave - 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most.
• YellowNest nursery scheme - to help working parents manage childcare costs.
• 25 days of Annual Leave (+ Public Holidays) - because taking time to rest matters.
• Private medical insurance - 100% employee cover, giving you complete peace of mind.
• Wellhub Subscription - gain access to thousands of gyms, classes and wellness apps, supporting both physical and mental wellbeing.
• Eye tests - because good work depends on good health.
• Personal development - dedicated support for learning, development, and leveling up over time.
• Employee Assistance Programme (EAP) - confidential wellbeing support, available whenever you need it.
• Bike2Work scheme and Season ticket loan - to make getting to work easier and greener.
• Octopus EV salary sacrifice - for a simpler, more sustainable way to drive electric.

Watch this space, we’re continuing to build this as we grow…

We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics.

We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.