Slosh-Damping Baffles for LNG Tank Models

ISEF Category: Engineering Technology: Statics and Dynamics

Subcategory: Naval Systems  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

A half-full tank can act like a giant moving weight. When the liquid shifts, it can push back with surprising force. That matters for LNG tankers, where slosh can stress the ship and its cargo system. You can study that force with a scaled tank, a hand-rocked cradle, and a load cell.

What Is It?

Sloshing happens when liquid inside a container keeps moving after the container starts to rock or stop. Think of a cup of water in your hand. If you swing your arm, the water lags behind and crashes into the side. In a ship tank, that motion can create repeated force spikes, which engineers try to reduce.

A baffle is an internal barrier that changes how the liquid moves. A printed lattice baffle works like a grid. It slows the flow, breaks up large waves, and can spread the energy into smaller motions. Your project asks a simple question: which baffle design cuts the slosh force the most in a scaled tank?

This topic sits at the intersection of mechanics and ship design. You are not just asking whether the liquid moves. You are measuring how much force the moving liquid pushes onto the tank platform, then comparing that force across designs.

Why This Is a Good Topic

This is a strong science fair topic because you can change one design feature, measure a clear response, and compare results with data. You can test baffle geometry, fill level, or rocking pattern without needing a university lab. The project connects to real engineering problems in LNG transport, where reducing slosh can improve safety and efficiency. You will learn how to build fair tests, collect force data, and turn messy motion into usable numbers.

Research Questions

• How does lattice baffle porosity affect peak sloshing force in a scaled tank?
• What is the effect of baffle height on the average force recorded during repeated rocking?
• Does baffle placement near the center or near the tank ends reduce force spikes more effectively?
• To what extent does fill level change the benefit of printed baffles in a rocking tank?
• Which lattice pattern, square, hexagonal, or diagonal, produces the lowest force response?
• How does rocking frequency change the difference between a baffled tank and an unbaffled tank?

Basic Materials

• Scaled tank or clear rectangular container with a secure lid.
• Hand-rocked cradle or hinged platform that can hold the tank safely.
• Load-cell platform or force sensor with a data logger.
• Phone camera or high-frame-rate phone video.
• Digital scale for checking sample mass and fill mass.
• Measuring tape or ruler.
• 3D-printed lattice baffle prototypes.
• Water or a safe liquid surrogate.
• Waterproof tape, clamps, and cable ties.
• Notebook or spreadsheet for recording trials.

Advanced Materials

• Access to CAD software for baffle design iteration.
• 3D printer with multiple nozzle or infill settings.
• Multi-axis force sensor or load cell array.
• High-speed camera for tracking wave motion.
• Motion sensor or accelerometer for cradle motion profiling.
• Transparent acrylic tank with interchangeable inserts.
• Particle tracking dye or tracer particles for flow visualization.
• Digital data acquisition system for synchronized force and motion capture.
• Finite element or fluid simulation software for comparison with test data.

Software & Tools

• Excel: Organizes force traces, makes graphs, and compares trial averages.
• Google Sheets: Lets you log data, calculate summary statistics, and share charts easily.
• ImageJ: Measures wave height and slosh patterns from tank videos.
• Python: Cleans force data, finds peaks, and compares designs with simple statistics.
• Fusion 360: Helps you design and revise lattice baffles before printing them.

Experiment Steps

1. Define the exact tank shape, fill range, and rocking motion you will compare so every trial stays consistent.
2. Choose one baffle variable to change first, such as porosity, placement, or lattice pattern.
3. Plan a measurement setup that captures both force response and visible liquid motion at the same time.
4. Build a baseline test with no baffle so you have a control case for every later comparison.
5. Decide how you will summarize each run, such as peak force, average force, or force variability.
6. Set rules for repeat trials, outlier handling, and fair comparisons across designs.

Common Pitfalls

• Using a cradle motion that changes from trial to trial, which makes force differences hard to trust.
• Letting the tank shift on the load cell platform, which adds extra force noise that is not true sloshing.
• Comparing baffles with different mass or thickness, which confounds geometry with weight.
• Filling the tank inconsistently, which changes the wave mode and masks the baffle effect.
• Recording force data without matching it to the rocking phase, which makes peak events easy to miss.

What Makes This Competitive

A stronger version of this project goes past simple before-and-after testing. You can compare multiple baffle geometries, test several fill levels, and report both force reduction and flow behavior. Better entries also use clean statistics, repeated trials, and a clear control. If you connect your results to a design rule, such as which lattice shape works best under which rocking condition, your project starts to feel like real engineering research.

Project Variations

• Test how the same lattice baffle performs in fresh water versus salt water to see whether fluid properties change the slosh response.
• Compare a printed lattice baffle with a solid plate baffle to separate porosity effects from blockage effects.
• Measure slosh force at different tank aspect ratios to see whether the best baffle design depends on tank shape.

Learn More

• NASA NTRS: Search for reports on liquid sloshing, tank dynamics, and spacecraft propellant management, which use the same physics ideas.
• NOAA Ocean Explorer: Use the site to review ship stability basics and marine engineering context.
• USGS Water Science School: Read plain-language explanations of waves, motion, and fluid behavior in containers.
• MIT OpenCourseWare: Search for fluid mechanics and dynamics course notes to review sloshing and resonance concepts.
• PubMed: Search for review articles on liquid sloshing in tanks and vibration damping for engineering comparisons.