- Marthijn Tuinstra, Scientist Principal at NLR, is specialized in aeroacoustics;<\/li>
- He is concerned with minimizing aircraft noise without compromising performance;<\/li>
- His contributions include the development of the NORAH model, a European approach to modeling helicopter noise.<\/li><\/ul><\/div>\n\n\n\n
A feeling of awe<\/h2>\n\n\n\n
\u201cFor me, aviation has always induced a feeling of awe. That we can fly at all is an amazing feat. It\u2019s a continuous quest for a balance between all sorts of different aspects \u2013 strength, weight and aerodynamics, and also noise. That\u2019s true for all machines, but the considerations are more extreme in aviation. An aircraft has to be lightweight and efficient, for instance, and at the same time strong too. Those powerful contrasts and the technical challenges they lead to are something I find absolutely fascinating.\u201d<\/p>\n\n\n
<\/a><\/div><\/div>Linking technology and tactics for the Defence Department<\/div>Carlina Grispen grew up in the shadow of Volkel military air base. It\u2019s no coincidence that she was interested in F16 at a young age already. <\/div><\/div><\/div>\n\n\n![\"\"](\"https:\/\/archive.ioplus.nl\/wp-content\/uploads\/2023\/12\/Participants-Workshop-1004x748.jpg\")
Marthijn at a workshop from the Japan Aerospace Exploration Agency<\/figcaption><\/figure>\n\n\n\n Research in Japan<\/a><\/h2>\n\n\n\n
After completing his studies in Aerospace Technology at Delft Technical University (TU Delft), he left for Japan to spend a year doing research at the Japan Aerospace Exploration Agency (JAXA). \u201cI wanted to see how I\u2019d cope on the other side of the world, in a completely different culture. It was a genuine eye-opener and it taught me that there\u2019s more than one way to set up a society. Take the social safety net, for instance, which is assisted less by the authorities in Japan than it is in the Netherlands. We look to the government pretty quickly, but there they look a lot more to companies and their families. And it works, too.\u201d<\/p>\n\n\n\n
While he was there, he became familiar with the field of aeroacoustics, as well as meeting his current life partner. He still flies back regularly with his family to the country he finds so special.<\/p>\n\n\n\n
NORAH: a European approach for modelling noise nuisance from helicopters<\/h2>\n\n\n\n
The Aeroacoustics group that Marthijn works in focuses in particular on one consideration: reducing aircraft noise without significantly affecting flight performance. His research is a combination of experimental aeroacoustics, experimental aerodynamics and aircraft noise modelling. A striking example of the last of those aspects is the NORAH model, which can calculate the noise burden of helicopters. Until recently, the noise impact of helicopters was worked out using a model for fixed-wing aircraft. The European Commission (EC) issued a tender in 2015 for developing a method for helicopter noise. A consortium led by NLR, working with Anotec Engineering and SINTEF, succeeded in winning the order. Within five years, they had put together a prototype\u00a0noise prediction tool for helicopters<\/a>.<\/p>\n\n\n\n
![\"\"](\"https:\/\/archive.ioplus.nl\/wp-content\/uploads\/2023\/12\/NORAH-1004x671.jpg\")
The sound hemispheres of the NORAH model. Image: NLR<\/figcaption><\/figure>\n\n\n\n \u201cWhat makes a helicopter different from an aeroplane is that the noise emissions depend heavily on the flying conditions and on the direction of flight. In other words, where you are with respect to the chopper is one of the factors determining the perceived nuisance. That aspect was not included in the standard methods and we had to work out how to get it into this model.\u201d<\/p>\n\n\n\n
They managed that by <\/a>expressing the helicopter\u2019s noise emissions in what are referred to as \u2018noise hemispheres\u2019. These half-ball shapes let the consortium record the noise source levels as radiated in every direction. To populate a database of noise hemispheres with suitable source data, noise measurement projects were carried out for eleven types of helicopters. To allow measurements to be made for multiple emission angles at the same time (i.e. where the sound is coming from), the consortium used a four-hundred metre long row of microphones on the ground. The NORAH model is already being used in the Netherlands, but the ultimate goal is that there should be a standardised model for all EU member states.<\/p>\n\n\n\n
He is proud that a model his group helped to develop will probably shortly be in use throughout Europe. \u201cTurning an idea into a fully-fledged working model and having a genuine social impact as a result, well, that\u2019s really satisfying.\u201d<\/p>\n\n\n\n
Balance between scientific and industrial applied research<\/h2>\n\n\n\n
Marthijn finds it difficult to strike a balance between industry on the one hand, which benefits more from practically-oriented research questions, and more innovative and fundamental research on the other. \u201cThe focus at NLR is on applied research, but you sometimes need studies at a more fundamental level too if innovations are to be achieved. That kind of research is largely done at the technical universities, where scientists \u2013 often still young ones \u2013 think out and test completely new ideas at the conceptual level.\u201d<\/p>\n\n\n\n
In his role as principal scientist, he has for instance worked with TU Delft on a flow measurement technique that works using small soap bubbles filled with a little helium. Those bubbles have precisely the same density as air and so they can follow the airflows precisely. That not only generates magical images when the soap bubbles are illuminated with lasers but also now allows large-scale flow measurements to be carried out around wind-tunnel models in industrial tests. <\/p>\n\n\n\n
\u201cWithout that cooperation, in which graduate students devoted four years of their full attention, creativity and development to setting up the technique, we wouldn\u2019t have been in a position to offer this measurement method to our clients today. Making sure that these two worlds \u2013 the scientific and industrial aspects of applied research \u2013 come together is precisely the kind of bridging function that I think NLR ought to be fulfilling.\u201d<\/p>\n\n\n\n
It is typical of the interview: before you know it, Marthijn has moved on to yet another aspect of his work that he finds so interesting. And there is that same leitmotif<\/em> again: weighing things up against each other. \u201cFor me, it\u2019s not about seeing a really neat aircraft flying. For me, it\u2019s about the extremes: how silent can we make an aircraft, without compromising on performance? That\u2019s the challenge for me, as well as perhaps being a bit of the magic of aviation too.\u201d<\/p>\n\n\n
<\/a><\/div><\/div>Turning additive manufacturing into a standard production route for aerospace<\/div>The rule for every aviation application \u2013 whether it\u2019s new or already existing \u2013 is that it\u2019s got to become lighter and more cost-efficient.<\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"Marthijn Tuinstra is involved in aeroacoustics: the noise that is created by airflows. His career focuses on minimising aircraft noise without compromising on performance. \u201cFor me, it\u2019s about the extremes: how silent can we make an aircraft, without compromising on performance? That\u2019s the challenge for me, as well as perhaps being a bit of the […]<\/p>\n","protected":false},"author":1744,"featured_media":494925,"comment_status":"open","ping_status":"closed","sticky":false,"template":"views\/single-partner.blade.php","format":"standard","meta":{"_acf_changed":false,"advgb_blocks_editor_width":"","advgb_blocks_columns_visual_guide":"","footnotes":""},"categories":[26049],"tags":[82906,48777,79631],"location":[6763],"article_type":[6758],"serie":[],"archives":[],"internal_archives":[],"reboot-archive":[],"class_list":["post-466921","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mobility","tag-aeroacoustics","tag-nlr","tag-nlr-people","location-netherlands","article_type-interview"],"blocksy_meta":[],"acf":{"subtitle":"In the series \u2018NLR People\u2019, we show you who the experts at the Royal Netherlands Aerospace Centre are. In this sixth episode: principal scientist and aeroacoustics specialist. Marthijn Tuinstra.","text_display_homepage":false},"author_meta":{"display_name":"Aafke Eppinga","author_link":"https:\/\/ioplus.nl\/archive\/author\/aafke-eppinga\/"},"featured_img":"https:\/\/ioplus.nl\/archive\/wp-content\/uploads\/2023\/12\/Marthijn.jpg","coauthors":[],"tax_additional":{"categories":{"linked":["Mobility<\/a>"],"unlinked":["Mobility<\/span>"]},"tags":{"linked":["aeroacoustics<\/a>","NLR<\/a>","NLR People<\/a>"],"unlinked":["aeroacoustics<\/span>","NLR<\/span>","NLR People<\/span>"]}},"comment_count":"0","relative_dates":{"created":"Posted 2 years ago","modified":"Updated 2 years ago"},"absolute_dates":{"created":"Posted on January 2, 2024","modified":"Updated on January 2, 2024"},"absolute_dates_time":{"created":"Posted on January 2, 2024 6:30 am","modified":"Updated on January 2, 2024 6:30 am"},"featured_img_caption":"","series_order":"","_links":{"self":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts\/466921","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/users\/1744"}],"replies":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/comments?post=466921"}],"version-history":[{"count":0,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts\/466921\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/media\/494925"}],"wp:attachment":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/media?parent=466921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/categories?post=466921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/tags?post=466921"},{"taxonomy":"location","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/location?post=466921"},{"taxonomy":"article_type","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/article_type?post=466921"},{"taxonomy":"serie","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/serie?post=466921"},{"taxonomy":"archives","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/archives?post=466921"},{"taxonomy":"internal_archives","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/internal_archives?post=466921"},{"taxonomy":"reboot-archive","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/reboot-archive?post=466921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![<\/a>expressing the helicopter\u2019s noise emissions in what are referred to as \u2018noise hemispheres\u2019. These half-ball shapes let the consortium record the noise source levels as radiated in every direction. To populate a database of noise hemispheres with suitable source data, noise measurement projects were carried out for eleven types of helicopters. To allow measurements to be made for multiple emission angles at the same time (i.e. where the sound is coming from), the consortium used a four-hundred metre long row of microphones on the ground. The NORAH model is already being used in the Netherlands, but the ultimate goal is that there should be a standardised model for all EU member states.<\/p>\n\n\n\nHe is proud that a model his group helped to develop will probably shortly be in use throughout Europe. \u201cTurning an idea into a fully-fledged working model and having a genuine social impact as a result, well, that\u2019s really satisfying.\u201d<\/p>\n\n\n\nBalance between scientific and industrial applied research<\/h2>\n\n\n\nMarthijn finds it difficult to strike a balance between industry on the one hand, which benefits more from practically-oriented research questions, and more innovative and fundamental research on the other. \u201cThe focus at NLR is on applied research, but you sometimes need studies at a more fundamental level too if innovations are to be achieved. That kind of research is largely done at the technical universities, where scientists \u2013 often still young ones \u2013 think out and test completely new ideas at the conceptual level.\u201d<\/p>\n\n\n\nIn his role as principal scientist, he has for instance worked with TU Delft on a flow measurement technique that works using small soap bubbles filled with a little helium. Those bubbles have precisely the same density as air and so they can follow the airflows precisely. That not only generates magical images when the soap bubbles are illuminated with lasers but also now allows large-scale flow measurements to be carried out around wind-tunnel models in industrial tests. <\/p>\n\n\n\n\u201cWithout that cooperation, in which graduate students devoted four years of their full attention, creativity and development to setting up the technique, we wouldn\u2019t have been in a position to offer this measurement method to our clients today. Making sure that these two worlds \u2013 the scientific and industrial aspects of applied research \u2013 come together is precisely the kind of bridging function that I think NLR ought to be fulfilling.\u201d<\/p>\n\n\n\nIt is typical of the interview: before you know it, Marthijn has moved on to yet another aspect of his work that he finds so interesting. And there is that same leitmotif<\/em> again: weighing things up against each other. \u201cFor me, it\u2019s not about seeing a really neat aircraft flying. For me, it\u2019s about the extremes: how silent can we make an aircraft, without compromising on performance? That\u2019s the challenge for me, as well as perhaps being a bit of the magic of aviation too.\u201d<\/p>\n\n\n<\/a><\/div><\/div>Turning additive manufacturing into a standard production route for aerospace<\/div>The rule for every aviation application \u2013 whether it\u2019s new or already existing \u2013 is that it\u2019s got to become lighter and more cost-efficient.<\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"Marthijn Tuinstra is involved in aeroacoustics: the noise that is created by airflows. His career focuses on minimising aircraft noise without compromising on performance. \u201cFor me, it\u2019s about the extremes: how silent can we make an aircraft, without compromising on performance? That\u2019s the challenge for me, as well as perhaps being a bit of the […]<\/p>\n","protected":false},"author":1744,"featured_media":494925,"comment_status":"open","ping_status":"closed","sticky":false,"template":"views\/single-partner.blade.php","format":"standard","meta":{"_acf_changed":false,"advgb_blocks_editor_width":"","advgb_blocks_columns_visual_guide":"","footnotes":""},"categories":[26049],"tags":[82906,48777,79631],"location":[6763],"article_type":[6758],"serie":[],"archives":[],"internal_archives":[],"reboot-archive":[],"class_list":["post-466921","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mobility","tag-aeroacoustics","tag-nlr","tag-nlr-people","location-netherlands","article_type-interview"],"blocksy_meta":[],"acf":{"subtitle":"In the series \u2018NLR People\u2019, we show you who the experts at the Royal Netherlands Aerospace Centre are. In this sixth episode: principal scientist and aeroacoustics specialist. Marthijn Tuinstra.","text_display_homepage":false},"author_meta":{"display_name":"Aafke Eppinga","author_link":"https:\/\/ioplus.nl\/archive\/author\/aafke-eppinga\/"},"featured_img":"https:\/\/ioplus.nl\/archive\/wp-content\/uploads\/2023\/12\/Marthijn.jpg","coauthors":[],"tax_additional":{"categories":{"linked":["Mobility<\/a>"],"unlinked":["Mobility<\/span>"]},"tags":{"linked":["aeroacoustics<\/a>","NLR<\/a>","NLR People<\/a>"],"unlinked":["aeroacoustics<\/span>","NLR<\/span>","NLR People<\/span>"]}},"comment_count":"0","relative_dates":{"created":"Posted 2 years ago","modified":"Updated 2 years ago"},"absolute_dates":{"created":"Posted on January 2, 2024","modified":"Updated on January 2, 2024"},"absolute_dates_time":{"created":"Posted on January 2, 2024 6:30 am","modified":"Updated on January 2, 2024 6:30 am"},"featured_img_caption":"","series_order":"","_links":{"self":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts\/466921","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/users\/1744"}],"replies":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/comments?post=466921"}],"version-history":[{"count":0,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/posts\/466921\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/media\/494925"}],"wp:attachment":[{"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/media?parent=466921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/categories?post=466921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/tags?post=466921"},{"taxonomy":"location","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/location?post=466921"},{"taxonomy":"article_type","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/article_type?post=466921"},{"taxonomy":"serie","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/serie?post=466921"},{"taxonomy":"archives","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/archives?post=466921"},{"taxonomy":"internal_archives","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/internal_archives?post=466921"},{"taxonomy":"reboot-archive","embeddable":true,"href":"https:\/\/ioplus.nl\/archive\/wp-json\/wp\/v2\/reboot-archive?post=466921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}](\"https:\/\/www.nlr.org\/wp-content\/uploads\/2023\/12\/NORAH.jpg\"){kind=link}