MSc Thesis project Spillway operation safety with respect to air demand/supply

About the thesis

The discharge capacity of the spillway is an issue that concerns the safety of a dam facility. In addition to structural stability, the spillway operation should also be free of undesirable negative air pressure, vibrations etc. As known, high-velocity spillway flow entrains air that is also transported by the flow. This might give rise to formation of air cavity with negative air pressure at such spillways as piano key weirs, labyrinth weirs and fuse gates featuring falling water jets. To understand the two-phase behhaviours is essential for spillway operation and potential countermeasures. As prototype air flows can not be correctly modelled in the laboratory, CFD plays a unique role in this context. This study is closely related to the ongoing upgrade projects by dam owners.

Thesis goal/purpose

One spillway type (piano key weirs, labyrinth weirs or fuse gates) is to be chosen, for which experimental data are available. The project aims to achieve the following goals.

(a) To simulate overflow and two-phase patterns at different discharges.

(b) To compare CFD results with experimental data.

(c) To clarify the scale effects of laboratory models.

(d) To suggest potential countermeasures and risk reduction.

Execution

With a previous laboratory model in the background, the study is executed with the help of CFD modeling with ANSYS FLUENT. The previous model tests will be reviewed. Representative flow cases are simulated so as to capture the worst and most unfavorable operation scenario that gives rise to damages. Potential countermeasures are also examined in the modeling.

For the students

• To get familiar with the ongoing dam-safety projects in the country
• To learn about hydraulic model tests
• To learn the fundamental knowledge of CFD
• To develop CFD skills for simulations of spillway flows

The project consists of the following aspects.

1. Background and literature review
2. Data collection (spillway geometry and flows)
3. Learning of CFD techniques
4. CFD model setup with experimental verification
5. CFD simulations, result analyses etc.
6. Report writing

We are looking for a student or two to join our journey towards  fossil freedom. You are soon to be graduated from your academic studies. You also identify yourself with our principles: active, open, positive and safe.

• Education - proper background is university education in civil (hydraulic) engineering, engineering physics or similar disciplines.
• Scope - the project corresponds to a 30 hp diploma work.
• Fluent written English.
• Strong interests in hydropower, dam safety and hydraulic engineering.
• The time of execution should be within four (4) months, accomplished before the end of 2026.

Start date: Mid-January 2026 or as agreed

Location: Vattenfall R&D in Älvkarleby or Stockholm – flexible based on agreement

Application: Please submit the following documents: (Incomplete applications will not be considered)

• CV with contact details
• Cover letter explaining your motivation for the project
• University transcript
• Name and contact information of your academic examiner (required at time of application)

Deadline: October 31, 2025

Applications are reviewed continuously, and the position may be filled before the deadline. We recommend applying as early as possible to secure your opportunity.

Contact person/supervisor at Vattenfall – James Yang, james.yang@vattenfall.com, phone 070-2723 200. Inquiry can be made by phone.

Diversity & inclusion - in everything we do

At Vattenfall we build on the fact that diverse teams can outperform homogeneous teams. But we can only unleash and leverage the power of diversity, if we make everybody feel included. Read more about our important work on diversity & inclusion https://careers.vattenfall.com/about-us/diversity-and-inclusion/

About Vattenfall

We have been electrifying industries, powering homes and transforming life through innovation and collaboration for more than 100 years. Empowered by our goal, we are determined to enable fossil free living within one generation. To succeed we, as one of Europe's leading energy companies, must be fossil-free ourselves. But that’s not enough. That’s why we are looking beyond our own industry, to see where we can really make a difference. Join us in our journey towards a fossil-free life within one generation.

Want to learn more about what we do? Visit www.vattenfall.com.

Since Vattenfall is a part of the Swedish critical infrastructure, many of our services are security classed. If this position is security classed the final candidates might be subjected to a security vetting process, according to the Swedish legislation.

Power Climate Smarter living - that’s our purpose. We are looking for the brightest students to make this happen. Together you will contribute to a fossil free future. You will have a unique position to contribute to our purpose. All we ask from you is to use your Superpowers and share your energy to help us achieve our goal.