Numerik Strömungsverhältnisse an einem Surfbrett


Prof. Dr. med. Dr. h. c. Heinrich Iro

Numerical study on four fin configurations for surfboards

Until now, the surfboard shapers’ experience highly dominates surfboard development in design and construction. Just recently, the shapers started to use milling machines for the board’s fabrication. Nowadays plastics and epoxy compositions are the predominant materials for the fins. Using CFD can not only speed up the development of surfboard and fin design but can also improve the knowledge of the behavior of the complete surfboard system. The basic idea of our studies is to improve CFD models in order to acquire a knowledge base for the fluid dynamical characteristic of the surfboard system.

The behavior of the lift and drag coefficients shows significant variations between the 24 different fin positions. Placing the fins closer to the outline curve of the surfboard generates higher maximum lift and drag forces. An increased angle of attack results in a decrease of the lift and drag forces, since the rear outside fin comes to lie further in the slipstream of the front outside fin. To get appraisal factors for the surfboards stability and maneuverability the yaw and roll moments were established. Both moments arise simultaneously and are strongly dependent on lift and drag coefficients.

Three-dimensional rectangular fluid volume with the inserted fins. b) Velocity field which governs around the four fins at an angle of attack of 45°.

Numerical investigation of a surfer-surfboard-system on a free surface

CFD is used in nearly all kinds of sports to achieve better equipment and performances, but in surfboard design and construction, still, the surfboard shapers’ experience is highly dominating. The high spatial and temporal resolutions in combination with unconfined access to the simulation region are great advantages of CFD compared to the still existing try and error method with a physical test setup.
The basic idea of our studies is to develop a CFD model that can fully reproduce a surfer-surfboard-system interaction in static and dynamic common surf motions. If an adequate model is established, the next step is to acquire a knowledge base for the fluid dynamical characteristics of the surfer-surfboard-system and to define a system of objective parameters to categorize the abilities of a surfboard-fin-system.

To reach the previously described aim of objective parameters for categorizing the surfboard-fin-systems characteristics, we will investigate the following forces and moments:

  • Lift and drag of the fins
  • Buoyancy and drag of the surfboard
  • Yaw-, roll and pitch moments produced by the surfer-surfboard-system

We suppose that appraisal factors for the stability and maneuverability of the surfboard are the moments that are acting on the surfer-surfboard-system. The moments that arise simultaneously are strongly dependent on the lift and drag forces of the fins and the buoyancy and drag of the surfboard.

Three sides construction view of the surfboard to define the basic configurations like width, thickness, length, and rocker.
Three-dimensional geometry model of a 6’8’’ surfboard like it is placed on the free surface within STAR-CCM+.

Numerical study on a stationary wave for surfing

Surfing is well known as a sport at the coasts of Hawaii, Australia and California. Many surfers do not live next to the ocean where they can easily go surfing every day. Soon, resourceful surfers began to surf so-called stationary waves in rivers. The most famous river wave is the Eisbach-Welle in the center of Munich. This wave arises because of a constructional error at the Eisbach river. In other cities, artificial waves are promoted to allow such river surfing; e.g. Dauerwelle e.V. in Nuremberg in the Pegnitz river.
Using CFD can help to fully understand the mechanisms that are responsible for the emergence of a stationary artificial wave. By performing CFD simulation, we want to understand the mechanisms and relevant parameters of such artificial waves. This will be the basis for future studies, where actual ocean surfspot setups will be simulated to increase our understanding of the occurring processes.

During some test runs and the grid independence study, it was found that there is a significant relationship between the inflow velocity of the stream current, the volume flow of the water over the ramp and the water height downstream of the ramp to produce an adequate stationary wave.

2D cut of the simulation region: (1) Inlet and outlet boundary, (2) Visible Multiphase of air and water, (3) Ramp and barrier, and (4) the developed stationary wave.
Velocity field which governs at the water surface.

Project period

Surfboard-Fin-Sytem since 08/2017

Stationary wave since 11/2018

Project staff

Sebastian Falk M. Sc.
Telefon: 09131 85-32607
Fax: 09131 85-32687
Bernhard Jakubaß M. Sc.
Telefon: 09131 85-43973
Fax: 09131 85-39272



Prof. Dr. med. Rolf Janka, Radiologie, Universitätsklinikum Erlangen

Dr. Roberto Grosso, Lehrstuhl für Informatik 9 (Graphische Datenverarbeitung), FAU Erlangen-Nürnberg

Prof. Dr.-Ing. Stefan Becker, Lehrstuhl für Prozessmaschinen und Anlagentechnik, FAU Erlangen-Nürnberg

Jerry O’Keefe, Soul Stix Surfboards, San Clemente, CA, USA

Tom O’Keefe, Daum Tooling Inc., San Clemente, CA, USA

Stationary wave

Univ.-Prof. Dr.-Ing. habil. Markus Aufleger, Arbeitsbereich Wasserbau am Institut für Infrastruktur Universität Innsbruck, Österreich


Felix Böschen under the supervision of Dr.-Ing. Stefan Kniesburges, Prof. Dr.-Ing. Michael Döllinger and Prof. Dr.-Ing. Stefan Becker: Numerische Analyse der Hydrodynamik eines Drei-Finnen-Surfboard-Setups (Master Thesis, 2017).

Sebastian Falk under the supervision of Dr.-Ing. Stefan Kniesburges, Prof. Dr.-Ing. Michael Döllinger and Prof. Dr.-Ing. Stefan Becker: CFD simulation of four fin configurations and their impact on fluid dynamical characteristics (Master Thesis, 2018).

Birgit Schweinesbein under the supervision of Prof. Dr.-Ing. Michael Döllinger in cooperation with FH-Nürnberg: Software for surfboard surface registration and reconstruction from CT imaging (Master Thesis, 2018).


Phoniatrie und Pädaudiologie
Dr. med. Anne Schützenberger
Waldstr. 1
91054 Erlangen

Telefon: 09131 85-32782
Telefax: 09131 85-32687

So finden sie uns

Die Abteilung Phoniatrie und Pädaudiologie finden Sie in Räumlichkeiten im 3. und 4. OG des Cicero-Gebäudes. Zur Orientierung melden Sie sich bitte an der Pforte der HNO-Klinik in der Waldstraße 1.

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Frau Dr. rer. medic. Dipl. Log. Anke Ziethe habilitierte sich am 21.06.19. Wir gratulieren!

Frau Dr. Anke Ziethe erhielt im Mai 2019 auf dem Annual Symposium (Care of the Professional Voice) der The Voice Foundation in Philadelphia (USA) den Preis "Spasmodic Dysphonia Research Award" für das Forschungsvorhaben "Analysis and Training of Feedback Mechanisms for Phonation and Speech of Patients with Muscle Tension Dysphonia (MTD)".

Im Mai 2019 besucht Frau Professor Rita Patel die Abteilung zu einem Forschungsaufenthalt. Sie ist eine international anerkannte Kollegin und lehrt und forscht an der Indiana University Bloomington in den USA.

Die DFG hat im Januar 2019 für drei Jahre das Forschungsprojekt „Induzierte Asymmetrien im exzidierten Kehlkopfmodell: Einfluss von Mukuseigenschaften auf Bewegung und Akustik“  bewilligt.

Die DFG hat im Dezember 2018 für drei Jahre das Forschungsprojekt „Chronical electrical stimulation for treatment of presbyphonia“ bewilligt. Das Projekt wird in Kooperation mit Prof. Gugatschka (Graz) durchgeführt, der durch den FWF gefördert wird.

Frau Dr. med. Anne Schützenberger hat die erforderlichen Voraussetzungen des FEES Curriculums für neurogene Dysphagien erfüllt und am 13.11.18 das FEES-Ausbilder-Zertifikat der DGN, DSG und DGG erhalten.


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