When Do JONSWAP Spectra Lead to Soliton Gases in Deep Water Conditions?

When a large number of solitons dominates the dynamics of a system, scientists describe this collective behaviour of solitons as a soliton gas. Soliton gases are currently the subject of intense practical and theoretical investigations. The existence of soliton gases has been confirmed in experiments, but is not clear what kind of sea states...

Les of hydrogen-enriched methane flames in a lean-burn combustor with axial air injection

Large eddy simulation (LES) paradigms are employed to analyse the internal flow field of a lean premixed swirl-stabilized combustor with axial air injection at both non-reacting and reacting conditions, for a methane and a methane-hydrogen fuel mixture. The thickened flame combustion model (TFM) with detailed chemical kinetic mechanism is...

Minimizing Cost In A 100% Renewable Electricity Grid: A Case Study Of Wave Energy In California

Wave energy converters have yet to reach broad market viability. Traditionally, levelized cost of energy has been considered the ultimate stage gate through which wave energy developers must pass in order to find success (i.e., the levelized cost of wave energy must be less than that of solar and wind). However, real world energy decisions are...

Performance Modelling Of Flap-Type Wave Energy Converter Array: Flaps With Various Dynamic Characteristics

Generally, it is expected that the total power of N energy converters in an array will be less than N times the power of a single operative converter. The goal of this paper is to enhance the oscillation of the flap-type WEC and consequently the energy extraction of the whole array in front of a coastal structure. Flaps in an array show...

Environmental Extreme Conditions For A Wave Energy Converter: An Integrated Wave-Structure Approach

The process of finding values of extreme waves and their impacts on wave energy converter (WEC) responses, depends on both wave resources and WEC dynamic characteristics. A wide range of waves can influence the reliability of operation and survivability of a WEC. In this paper, a methodology is described to find specific values of wave heights...

A Curved Compliant Differential Mechanism With Neutral Stability

Differential mechanisms are remarkable mechanical elements that are widely utilized in various systems; nevertheless, conventional differential mechanisms are heavy and difficult to use in applications with limited design space. In this paper, a curved lightweight compliant type of differential mechanism is presented. This mechanism acquires...

Subsea buoyancy and gravity energy storage system for deep-water applications: A preliminary assessment

This article presents a preliminary assessment of a subsea buoyancy and gravity energy storage system (SBGESS). The storage device is designed to power an off-grid subsea water injection system to be installed at the Libra oil field in Brazil at 2000 m below sea level. Two 12MW floating wind turbines provide the energy supply. The system...

Personalized product design through digital fabrication

Personalized designs bring added value to the products and the users. Meanwhile, they also pose challenges to the product design process as each product differs. In this paper, with the focus on personalized fit, we present an overview as well as details of the personalized design process based on design practice. The general workflow of...

Fatigue Strength Of Fixed Offshore Structures Under Variable Amplitude Loading Due To Wind, Wave, And Ice Action

Fixed offshore wind turbines are increasingly developed for high latitude areas where not only wind and wave loads need to be considered, but also moving sea ice. Current structural design rules do not adequately consider the effect of ice loading on fatigue life, due to missing studies on fatigue strength of welded joints under combined wind,...

Ice Basin Tests For Ice-Induced Vibrations Of Offshore Structures In The Shiver Project

With the recent surge in development of offshore wind in the Baltic Sea, Bohai Sea and other ice-prone regions, a need has arisen for new basin tests to qualify the interaction between offshore wind turbines and sea ice. To this end, a series of model tests was performed at the Aalto ice basin as part of the SHIVER project. The tests were aimed...

Classification Of Ice-Induced Vibration Regimes Of Offshore Wind Turbines

Ice-induced vibrations of offshore wind turbines on monopile foundations were investigated experimentally at the Aalto Ice Tank. A real-time hybrid test setup was developed allowing to accurately simulate the motion of a wind turbine in interaction with ice, incorporating the multi-modal aspects of the interaction and the effect of simultaneous...

Design optimization of a high-speed twin-stage compressor for next-gen aircraft environmental control system

The environmental control system (ECS) is the largest auxiliary power consumer, i.e, around 75% of non-propulsive power, among the aircraft subsystems. The adoption of a novel ECS architecture, based on an electrically-driven vapor compression cycle system, can enable a twofold increase of coefficient of performance (COP), as compared to the...

Operating Characteristics of a Flameless Combustor Obtained By Experiments Informed Modelling

Flameless Combustion is an interesting low NO_x combustion technology for gas turbine engines. In order to design systems for stringent performance standards, it is important to understand emission formation in this regime. To this end, the characteristics of a combustor capable of operating in the Flameless regime are studied....

A Novel Engine Architecture for Low NOx Emissions

The fuel efficiency of turbofan engines has improved significantly, hence reducing aviation's CO2 emissions. However, the increased operating pressure and temperature for fuel efficiency cause adverse effects on NOx emissions. Therefore, a novel engine concept, which can reduce NOx emissions without affecting the cycle efficiency, is of high...