Applications of fluid dynamics, May 2024

Fluid dynamics is a discipline of mechanical engineering, and describes the flow of fluids - liquids and gases. The subject has been largely an experimental one, dating back thousands of years when water supply and sailing were two of the main application.  Even today, experiments play a large part but applied mathematics and numerical analysis play an increasingly valuable supporting role.

June's meeting covered a wide range of topics from water and wind power; to airplanes and Formula 1 cars; oceans and atmospheres; and flow-induced structural disasters.

Click here for slides of the presentation.

The history of the jet Engine, 22nd February 2024

The STEM Group presentation in February covered the history of the jet engine from the early days of Frank Whittle’s machine to the development of Rolls Royce’s Ultra Fan, the largest jet engine ever produced.  Whittle had many difficulties securing Government funding in the lead-up to WW2 and, although he was eventually able to secure enough to build an engine and fly it, the opportunity to develop a jet fighter in time to participate meaningfully in the war was lost.  He played no part in the aircraft industry in later years and emigrated to America where he received many awards for his work.

Here is the link to the Powerpoint presentation.  Click on View; Slideshow.

u3a STEM Group discussion - home heating, solar panels, electric cars and food, 28th September 2023

In a change to our usual format, the STEM Group will next meet on 28th September 2023 for a round-table discussion on elements of reducing our carbon footprint which might affect us personally, e.g. heat pumps, solar panels, electric cars and food consumption, which was first presented in October 2022.

The material for that presentation can be found here in Powerpoint form: 

Home heating and power, transport and food

Navigation, its history, science and technology, February 2023

 Here is a link to the presentation on Navigation, its history, science and technology, February 2023.

Smart meters and Demand Flexibility Service, 30th January 2023

Smart meters and Loop Energy 

The subject of smart meters is one that we might cover in the future but in the meantime, let me share my own recent experience.

Since I switched supplier just over year ago, my smart meter itself continued to send readings to EON  every half hour but the monitor inside the house failed so I now have no access to any measure of my instantaneous gas or electricity consumption.  However, there is an app called Loop which can be downloaded to a tablet or smartphone from e.g the  Android Playstore and which can access the national database of household electricity use.

After downloading, you need to provide Loop with email and home addresses together with a four digit code obtained from the Settings menu of your monitor (which will still display even though there is no network connection as in my case) so you cannot monitor your next door neighbour.

Loop will display graphs of your gas and electricity use (kWh) and costs at half-hourly, daily, weekly, monthly or yearly intervals.  The data is updated at 3-hour intervals so, again, does not provide instantaneous readings.  The Loop data is available in the home of course but also from anywhere you have internet access and might be similar to the energy suppliers’ own apps.

By examining how your use changes with time of day and day of the week etc some valuable information can be obtained on the relative importance of heating, lighting and hot water.  As a guide, an average household consumes on average 400W of electricity.  My overnight electricity use is 100W which is accounted for by a fridge and freezer and electronics on standby.  As for gas, here is an example of two days use in January.  In the evening of the second day (in green) I turned off the central heating and turned on a gas fire to heat just one room.  There was a not unimpressive 70% reduction.

Demand Flexibility Service - at last a use for smart meters

National Grid are supporting several Demand Flexibility Services with Octopus, British Gas, EDF and E.ON this Winter for households with smart meters.  Provided you reduce your usage by at least 40% of your baseline (your normal usage for the same period), your supplier will pay you for every kWh saved.  The aim is to reduce electricity use in the evening and avoid massive spikes in its price.

The Scheme was triggered for the first time between 4.30pm and 6pm on Monday last week with 400,000 eligible customers being paid £2.50 for reducing usage by an average of 60% - this compares with the 30p that you normally pay your supplier.  More energy was saved on Tuesday, when the payment was larger than on Monday.

Nationwide, the total amount of energy saved was about 250 megawatt hours (a single generating unit at Ratcliffe Power Station operating for half an hour) and it surprising that such a small reduction can trigger such large payments.  This is due to the extreme volatility of electricity prices (see below), a consequence of trying to control an essentially technical system using commercial means.

Volatile wholesale electricity prices; £500 per megawatt hour equates to 50p per kWh

Noise and Acoustics, 26th January 2023

 

Here is the link to material from the fifth STEM presentation Noise and Acoustics.  Click on it to start a Powerpoint presentation.

Noise and Acoustics

Websites and Blogs, November 24th 2022

Here is the link to material from the fourth STEM presentation Websites and Blogs.  Click on it to start a Powerpoint presentation.

Websites and Blogs