Combustion instabilities occur in the combustors of aero-engines and land-based gas turbines. They are particularly problematic for low-NOx combustors. They are caused by a two-way coupling between acoustic waves and unsteady heat release, which under some conditions causes oscillation amplitudes to successively increase. Due to the range of fluid length scales involved, from the fine turbulence associated with flame-front wrinkling to the long acoustic wavelengths, direct computation of combustion instability is generally prohibitively expensive. This means that simplified modelling is an attractive option, typically implementing separate but coupled models for the acoustic wave behaviour and the flame response to acoustic perturbations. During this workshop, we will explore low order modelling of combustion instabilities in simple combustors. The acoustic wave behaviour will be modelled using linear plane-wave methods, while the flame response will be captured via a variety of models, some analytical, some based on simulation/experimental data, some linear, some non-linear. Matlab and Simulink calculations of the combustor eigenmodes and oscillation time-histories will be obtained. This will be used as the basis for more advanced investigations, including feedback control, whereby the fuel flow rate to the flame is made to depend upon combustor pressure measurements in order to inhibit instability, and adjoint-based methods for choosing the sensor and actuator locations.

Invited Keynote speaker:

Prof. Aimee Morgans, Imperial College, London, UK

Venue:

The workshop will take place at the picturesque estate of Montestigliano in the heart of Tuscany. The village of Montestigliano is composed of 18th century buildings, typically of Tuscan architecture. Located 15 km south-west of Siena, it provides a stunning landscape and a stimulating environment for both intensive work and relaxation. The 18th century houses and farm buildings have been carefully restored to retain their original features common to Tuscan architecture.
For further information visit http://www.montestigliano.it/.

About ERCOFTAC Montestigliano Spring School

Ercoftac Montestigliano Spring School is an event for young scientists covering a specific multi-disciplinary and modern topic in fluid mechanics. Its format is based on an interactive teaching concept. Besides the traditional supervision by the student's advisor, the typical education of a PhD student seldom involves hands-on training under the guidance of a true expert in a particular and complementary field. University courses succeed in laying a foundation in rudimentary (and even a few specialized) concepts. Conferences, minisymposia and standard workshops expose young scientists to recent advances.In Montestigliano, students collaborate intensively during a full week in small groups under the guidance of a world-leading expert in a specialized topic.

Format:

The workshop starts with two or three (~2h long) lectures by the invited speaker on the chosen topic. During the week the students work in groups of 3-4. They are given a challenging project designed by the invited speaker and the organizers. The projects are often supplemented by Matlab codes and other material (papers, notes) that form an ideal starting point for the students. The projects are commonly divided into three categories: (A) basic concepts, (B) advanced concepts and (C) open questions at a research level. Students present their projects on the final day and submit a report 1-2 months after the workshop. In exceptional cases, these reports form the basis for a journal publication. The speaker and organizers are available during the entire week and work in close contact with the groups, helping out when difficulties arise or filling in missing knowledge.
Being in a remote area of Tuscany, the participants (organizers and student) are responsible for lunches and dinners. In this way, the student quickly become aquatinted with each other and a very warm and friendly atmosphere is created.

How to apply

Applications of prospective participants should contain:

1. A Curriculum Vitae (CV) or resume of the applicant (max one page
2. A short letter of purpose from the student (max one page), highlighting in particular the relevance of the workshop to his/her research topic.
A short description of the research topic should also be included.
3. A short letter of recommendation from the supervisor of the applicant (max one page).
This letter should be sent directly by the advisor to the organizers.
The applications can be submitted to any of the organizers.
Selected candidates will subsequently be notified and will receive a fellowship
that covers accommodation. Travel costs to and from the workshop venue have to carried by the home institute. Registration fee is 100€.

The deadline for applications is March 12, 2015.