Fluid Mechanics Section at the Technical University of Denmark (DTU, DTU Wind Energy is seeking a PhD student within the field of “Modeling of low frequency noise from wind turbines”.

In the past three decades the size of commercial wind turbines has increased from units of about 50 kW in the early 1980s to the latest multi-MW turbines with rotor diameters over 120 m. The overall goal is to reduce the cost price of the produced energy, and as long as increasing the size results in a reduction of the cost price. This up-scaling affects the noise spectra, where peak frequencies are moved to lower frequencies. Low frequency (LF) noise is often created from wind turbines in partial or in full wake of other wind turbines. Recent studies [1] show that the amplitude modulated (AM) noise during operation in wind shear, tower shadow and/or wake operation can result in significant extra annoyance.

Responsibilities and tasks 
The general scope of the PhD project is to develop an aero-acoustic simulation method for low frequency noise modeling based on the in-house Navier-Stokes/Actuator Line technique for Large Eddy Simulation.

The PhD project consists of 2 parts:

First, the flow-acoustics splitting technique [2-3] will be further developed to couple with the in-house Navier-Stokes/Actuator Line technique [4-5]. Large eddy simulation with turbulence inflow will be carried out. Validation and comparisons with existing measurements in the case of a wind turbine under wind shear and tower shadow will be carried out.

The second part is to simulate the noise generated from wind turbine in partial or full wake of an upstream turbine. Validation with measurements will be carried out. Furthermore, the noise sources of the turbine in wake will be identified which leads to develop an advanced noise control technique for wind turbines in wind farm.

Qualifications
Candidates should have a master’s degree in engineering or a similar degree with an academic level equivalent to the master’s degree in engineering.

Approval and Enrolment
The scholarships for the PhD degree are subject to academic approval, and the candidates will be enrolled in one of the general degree programmes of DTU. For information about the general requirements for enrolment and the general planning of the scholarship studies, please see the DTU PhD Guide.

We offer
We offer an interesting and challenging job in an international environment focusing on education, research, public-sector consultancy and innovation, which contribute to enhancing the economy and improving social welfare. We strive for academic excellence, collegial respect and freedom tempered by responsibility. The Technical University of Denmark (DTU) is a leading technical university in northern Europe and benchmarks with the best universities in the world.

Salary and appointment terms
The salary and appointment terms are consistent with the current rules for PhD degree students. The period of employment is 3 years. The place of work is DTU Risø Campus in Roskilde.

Supervisor team
Head supervisor: Wen Zhong Shen, Associate Professor, DTU Wind Energy
Co-supervisor: Wei Jun Zhu, Senior Researcher, DTU Wind Energy
Co-supervisor: Jens Nørkær Sørensen, Professor, PhD, DTU Wind Energy

Further information
Further information may be obtained from Associate Professor Wen Zhong Shen, tel.: +45 4525 4317. Please do not send applications to this e-mail address, instead apply online as described below.

You can read more about the Department on windenergy.dtu.dk.

Application
We must have your online application by 1 July 1 2013. Applications must be submitted as one pdf file containing all materials to be given consideration. To apply, please open the link « Apply online » and fill in the online application form, and attach all your materials in English in one pdf file. The file must include:

• A letter motivating the application (cover letter)
• Curriculum vitae
• Grade transcripts and BSc/MSc diploma
• Excel sheet with translation of grades to the Danish grading system (see guidelines and excel spreadsheet here)

Candidates may apply prior to ob­tai­ning their master’s degree, but cannot begin before having received it.

All interested candidates irrespective of age, gender, race, disability, religion or ethnic background are encouraged to apply.