Fluid Dynamics Expert - Fully Remote | Up to $110/hr

Obsidian; San Francisco (CA); Remote; USD 110,000 - 152,000; Part time

Job summary

Obsidian is seeking researchers to tackle research-level convection stability problems. You will engage with your subfield, producing fully reasoned outputs that others can verify. The role emphasizes written reasoning as a core deliverable.

This is a remote, project-based engagement with 10 hours per week over 8–10 weeks, starting immediately. Compensation is $80–$110 per hour based on subdomain match depth.

Qualifications

• PhD in a related field (fluid mechanics, applied mathematics, mechanical engineering).
• Published work on convection stability specifically.
• Verifiable publication record with DOIs/arXiv IDs.
• Working proficiency with LaTeX, Python and Jupyter.

Responsibilities

• Engage in research-level physics problems in your subfield.
• Create problems, solve them, review completed work, or audit it.
• Write reasoning as part of every assignment.

Skills

Boussinesq approximation

Linear stability analysis

Normal-mode perturbation expansion

Spectral eigenvalue methods

Darcy's law

Porous-medium flow

Buoyancy-driven flow

Education

PhD in fluid mechanics or applied mathematics or mechanical engineering

Tools

LaTeX

Python

Jupyter

VS Code

Job description

About the work

CritPt is a public benchmark of research-level physics challenges, built to test whether frontier AI models can carry out genuine physics research reasoning rather than textbook problem solving. The benchmark paper is arXiv:2509.26574 and we recommend reading it before applying. It will tell you quickly whether this work interests you.

We are engaging physicists to work on research-level physics problems in their own subfield. Depending on where your publication record fits, that can mean creating problems, solving them, reviewing completed work, or auditing it. We agree the specific assignment with you once you are matched to an area.

This is research-grade work rather than volume work. Whatever you produce has to be complete enough for another specialist in your subfield to follow and verify independently, so written reasoning is part of every assignment.

Research areas in this panel

Two areas, both on the linear stability of buoyancy-driven convection. We match narrowly: you need to have published on convection stability specifically, not on fluid dynamics broadly. Each area lists the methods it requires.

1. Rayleigh-Benard convection: linear stability with mixed boundary conditions: Rayleigh-Benard convection, Boussinesq approximation, linear stability analysis, normal-mode perturbation expansion, mixed mechanical and thermal boundary conditions, fixed-flux thermal forcing, marginal stability analysis, spectral eigenvalue methods.

2. Porous-medium (Rayleigh-Darcy) convection: linear stability: Darcy's law for porous-medium flow, Rayleigh-Darcy convection, Boussinesq buoyancy approximation, linear stability analysis, constant-flux and open boundary conditions, normal-mode perturbation expansion, marginal stability analysis, buoyancy-driven transport in saturated porous layers.

Methods we expect to find in your own publications

You should be able to point to your own papers demonstrating at least one of the following families:

• Boussinesq approximation and buoyancy-driven flow
• Linear stability analysis and normal-mode perturbation expansion
• Marginal stability analysis and critical Rayleigh number determination
• Spectral eigenvalue methods
• Darcy's law and porous-medium flow

Who we are looking for

A PhD in fluid mechanics, applied mathematics, mechanical engineering or a closely related field. This is a hard requirement. Postdoctoral researchers, research scientists and junior faculty are the strongest fit. Senior PhD students with a strong first-author record are welcome to apply.

Published work on convection stability specifically. This is the single most common reason we decline otherwise excellent researchers. Command of the methods is not enough if you have not published on the phenomenon itself.

A verifiable publication record. Three to five representative papers with DOIs or arXiv IDs, ideally from the last five years. First author strongly preferred. A journal DOI is expected here, since much of this literature is not on arXiv. Every paper you list will be checked against the public record.

Working proficiency with LaTeX, Python and Jupyter. Some familiarity with an agentic coding extension in VS Code is useful. Gaps there are acceptable if you declare them honestly.

English at B2 or above, including written reasoning. A large part of the value you add is how clearly you set out your argument.

Commitment and rate

10 hours per week, sustained across an 8 to 10 week window, starting immediately. Remote and asynchronous with no fixed hours.

$80 to $110 per hour, set by depth of subdomain match.