Research students - Natural environment

• PhD Student: Mohammadreza Mohammadi
• Supervisors: Prof Chris Baker & Prof Mark Sterling
• Duration: 2016-2020

Lodging, the permanent displacement of stems from the vertical and the associated issue of yield and quality reductions have received much attention over the last ten years. Much of this focus has been directed to crops such as wheat and barley. Ireland grows very high quality oats with the potential to significantly increase exports for human consumption and as equine feed however they are prone to lodging, but relatively little work has been undertaken in order to improve its lodging resistance. This lack of work is partly due to the complex nature of the plant and the multidisciplinary nature of the work; knowledge of crop physiology and wind engineering principles are required in order to scientifically model and hence understand the lodging process, and reduce lodging risk. Important gaps in knowledge are understanding how crops with inter-locking canopies interact with wind and lodge, how the strength of stems vary up the length of the stem and the root traits that determine anchorage strength. 

The proposed research combines the expertise of agronomists, crop physiologists and wind engineers in order to investigate lodging in oats. The research explores the applicability in field conditions of a theoretical model which has been developed by the team to assess lodging in oats. Through the use of a large number of field-scale trials, the model will be further developed and calibrated as appropriate. The model will then be used to investigate which plant parameters affect lodging the most and to specify the plant character values required for lodging proofness. The model will be used to quantify the effect of changes in agronomic practices on lodging risk, which will form the basis of an improved lodging risk and management scheme. It will also be used to guide the efforts of plant breeders by identification of the key traits for genetic improvement. The effect of possible climate change on the risk of lodging in the crop will also be investigated through the model. 

• PhD Student: Frederick Bourriez 
• Supervisors: Profs Chris Baker, John Bridgeman and Mark Sterling
• Duration: 2015-2018

The highest wind speeds on Earth often arise as a result of tornadoes. The May 2013 US tornadoes demonstrated yet again the power of these events and the complete devastation and consequent loss of life that can occur within a very short timescale. Further devastation and more deaths resulted a couple of weeks later when tornadoes occurred again in Oklahoma. North America is not alone in experiencing devastating tornado outbreaks with frequent tornado related damage reported on an annual basis across South America, Australia, Asia and Europe. Society’s risk to extreme storms such as tornadoes is increasing due to expanding and wealthier populations, with more valuable assets at risk. Debris has the propensity to get embedded within tornadoes and to reach significant speeds. The impact of such debris on engineering and non-engineering structures has the potential to cause more damage than the wind itself and to create further debris which in itself may be transported by the local wind field.

This research involves both physical and numerical simulations in order to track the path of debris items embedded within a transient wind field of a tornado. The simulations will be compared with existing theoretical models for debris flight and used to establish a set of guidelines for engineers.

• PhD Student: Stefanie Gillmeier
• Supervisors: Prof Mark Sterling & Dr Hassan Hemida
• Duration: 2015-2018

Tornadoes can generate wind speeds of significant magnitude which can result in devastating damage. To prevent this, a better understanding of wind and pressure fields within and near tornadoes is required. Obtaining real life data for such winds is fraught with challenges. For this reason, physical and numerical simulations are used to safely generate tornadoes under controlled conditions. Aim of this research is to improve the representation of full-scale tornadic events in physical tornado simulators.

Main research focus is to outline and discuss challenges when modelling tornado-like vortices experimentally focusing on the influence of the generator’s geometry on the flow and pressure field. Several different simulations will be undertaken, during which the dimensions of the simulator will be varied whilst the swirl and aspect ratio is kept constant. This fundamental work will, for the first time, enable a thorough comparison between simulations undertaken in different simulators to be appropriately interpreted.

• PhD Student: Amelia Rouse
• Supervisors: Dr Nicole Metje, Prof David Chapman, Prof Ian Jefferson
• Duration: 2015-2018

The research focuses on improving existing root anchorage failure models. The project aims to develop an improved model for the root-soil interaction by considering different root structures as well as soil types, compaction and water content amongst others. The objectives are to develop idealised root structures for the laboratory, which can then be instrumented with strain gauges and artificially ‘lodged’. This will be repeated for a number of different soil types and conditions.  Field trials in Ireland are used to inform, and validate, the findings from the laboratory.  

The result will be an improved model for root anchorage failure, which can then be used to produce plants with improved root anchorage characteristics. The data will be analysed using techniques such as spectral analysis, wavelet analysis and structural analysis.