Intern, R&D Graduate Summer - Computational Thermal and Fluid Mechanics, Hybrid

We are seeking a Graduate Student Intern to work with a team to develop algorithms, models and software to simulate compressible turbulent flows from subsonic to hypersonic Mach numbers. Specifically, during the summer of 2026, the successful candidate will assist our team with model development for the modeling of hypersonic ablation phenomena.

On any given day, you may be called on to:

• Analyze, develop, implement, and evaluate models and algorithms for compressible Direct Numerical Simulations (DNS), Large Eddy Simulations (LES), Reynolds Averaged Navier Stokes (RANS) simulations, and hybrid RANS/LES simulations
• Analyze and improve performance of codes on next generation computing architectures
• Support areas of development including: structured and unstructured high-order finite volume, finite difference, and finite element methods applied to transonic and hypersonic fluid flow; algorithms for GPUs, manycore, and other advanced architectures; mesh adaptation for exascale simulations; and coupling approaches for multi-physics problems such as conjugate heat transfer and fluid-structure interaction in high-speed flows
• Contribute to algorithms for simulating aerodynamic heating, aerothermodynamics and develop physical models for material response in hypersonic flow

The selected applicant can work a combination of onsite and offsite work. The selected applicant must live within a reasonable distance for commuting to the assigned work location when necessary.

At Sandia, we value the important work done by our interns and its contribution to National Security. Because of this, our interns earn competitive pay rates. Our pay structure is based on earned credit hours, classification, and degree level. Your pay rate will be determined during the hire process and included in your offer package. You can view the Intern Pay Rate chart here.

You bring the confidence and skills to be eligible for the job by meeting these minimum requirements:

• Earned bachelor's degree
• Currently attending and enrolled full time in the spring term immediately preceding the internship (or scheduled to graduate in the spring) in an accredited science, engineering, or math graduate program
• Minimum cumulative GPA of 3.0/4.0
• Ability to work up to 40 hours per week during the summer
• U.S. citizens, legal permanent residents, asylees or refugees in the U.S.

Note: If you have not yet started your graduate program, please apply to an undergraduate intern position.

• PhD candidate, in the aerospace engineering, mechanical engineering, or applied mathematics/computational engineering sciences (with concentration in fluid dynamics)
• Development experience in CFD for compressible high Reynolds number turbulent flows
• Experience with computational approaches (finite element, finite difference, and finite volume methods) for CFD simulations
• Experience with code development
• Experience working with a diverse team
• Good communication skills as evidenced by a history of publication of results in peer-reviewed journals and external presentations at appropriate scientific conferences

This posting will be open for application submissions for a minimum of seven (7) calendar days, including the 'posting date'. Sandia reserves the right to extend the posting date at any time.

The Computational Thermal and Fluid Mechanics Department (1541) develops advanced engineering analysis codes to execute on a variety of computing platforms from petaflop machines at SNL, LANL and LLNL to desktop workstations. These codes will be used to perform highly detailed simulations for use in the design, development and qualification of nuclear weapons. We also intend to continue our Center's history of collaborating with outside government agencies and commercial enterprises. The code development efforts are focused at providing analysis tools for other departments in the Engineering Sciences Center and other strategic partners. The code areas are thermal analysis, participating media radiation, fire environments, incompressible flow (with capillary hydrodynamics, drying, porous flow -- multi-physics), compressible flow (subsonic, transonic and hypersonic), and shock physics. The development teams also support work in solid mechanics and structural dynamics. Code teams are typically five to ten people, and strong interaction with the analysis teams is an important part of the code development process. Internal customers include the Defense Programs, Defense Systems and Assessments, and the Energy and Environment Sectors, in collaboration with other departments in the Center. In addition, the department has significant involvement with external industrial partners including industrial consortia.

Sandia National Laboratories is the nation's premier science and engineering lab for national security and technology innovation, with teams of specialists focused on cutting-edge work in a broad array of areas. Some of the main reasons we love our jobs:

• Challenging work with amazing impact that contributes to security, peace, and freedom worldwide
• Extraordinary co-workers
• Some of the best tools, equipment, and research facilities in the world
• Career advancement and enrichment opportunities
• Flexible work arrangements for many positions include 9/80 (work 80 hours every two weeks, with every other Friday off) and 4/10 (work 4 ten-hour days each week) compressed workweeks, part-time work, and telecommuting (a mix of onsite work and working from home)
• Generous vacation, strong medical and other benefits, competitive 401k, learning opportunities, relocation assistance and amenities aimed at creating a solid work/life balance*

World-changing technologies. Life-changing careers. Learn more about Sandia at: http://www.sandia.gov

*These benefits vary by job classification.

This position does not currently require a Department of Energy (DOE) security clearance.

Sandia will conduct a pre-employment drug test and background review that includes checks of personal references, credit, law enforcement records, and employment/education verifications. Furthermore, employees in New Mexico need to pass a U.S. Air Force background screen for access to Kirtland Air Force Base. Substance abuse or illegal drug use, falsification of information, criminal activity, serious misconduct or other indicators of untrustworthiness can cause access to be denied or terminated, resulting in the inability to perform the duties assigned and subsequent termination of employment. Under federal law, citizens and agents of the People's Republic of China, the Islamic Republic of Iran, the Democratic People's Republic of North Korea, and the Russian Federation are generally prohibited from accessing Sandia National Laboratories. Accordingly, such individuals will not be considered for employment unless they are also a citizen of the United States.

If hired without a clearance and it subsequently becomes necessary to obtain and maintain one for the position, or you bid on positions that require a clearance, a pre-processing background review may be conducted prior to a required federal background investigation. Applicants for a DOE security clearance need to be U.S. citizens. If you hold more than one citizenship (i.e., of the U.S. and another country), your ability to obtain a security clearance may be impacted.

Members of the workforce (MOWs) hired at Sandia who require uncleared access for greater than 179 days during their employment, are required to go through the Uncleared Personal Identity Verification (UPIV) process. Access includes physical and/or cyber (logical) access, as well as remote access to any NNSA information technology (IT) systems. UPIV requirements are not applicable to individuals who require a DOE personnel security clearance for the performance of their SNL employment or to foreign nationals. The UPIV process will include the completion of a USAccess Enrollment, SF-85 (Questionnaire for Non-Sensitive Positions) and OF-306 (Declaration of for Federal Employment). An unfavorable UPIV determination will result in immediate retrieval of the SNL issued badge, removal of cyber (logical) access and/or removal from SNL subcontract. All MOWs may appeal the unfavorable UPIV determination to DOE/NNSA immediately. If the appeal is unsuccessful, the MOW may try to go through the UPIV process one year after the decision date.

All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, or veteran status and any other protected class under state or federal law.

If you have a Medical Portable Electronic Device (MedPED), such as a pacemaker, defibrillator, drug-releasing pump, hearing aids, or diagnostic equipment and other equipment for measuring, monitoring, and recording body functions such as heartbeat and brain waves, if employed by Sandia National Laboratories you may be required to comply with NNSA security requirements for MedPEDs.

If you have a MedPED and you are selected for an on-site interview at Sandia National Laboratories, there may be additional steps necessary to ensure compliance with NNSA security requirements prior to the interview date.