Dr David M. Birch

Research Interests

Lead investigator, Surrey Fluid Sensor Development Initiative


Fundamental turbulence research

Isovorticity contours from DNS of a turbulent vortex, Re = 4000.

See Jammy et al. (2014) for details. 


 Passive and active flow control

Numerical simulation of asymmetric surface waves in a pressure sensing membrane.

(Collaboration with Imperial College London )

Industrial and applied aerodynamics

Array of medium-bandwidth velocity sensors, produced for a commercial partner.

See the Surrey Fluid Sensor Development Initiative page for more detail on our capability.

Research Collaborations

Current and recent research partners include



I deliver components of the following undergraduate modules at the University of Surrey:

I also deliver the following module as a Visiting Lecturer at Imperial College London

  • AE3 416       Advanced propulsion


I supervise undergraduate project teams, undergraduate summer research students, M.Eng. and M.Sc. project students, and Ph.D. research students. 

External examiner

I have served as the external examiner for the following degree courses at Southampton Solent university:

  • B.Eng. (Hons) Yacht & Powercraft Design
  • B.Eng. (Hons) Yacht Design & Production

Departmental Duties


I offer a variety of scientific and technical consulting services in the following fields:

We can also design and produce experimental models and bespoke sensing systems, and can provide full experimental facilities and support.

For more information or for examples of previous work, please contact me.

Contact Me

Phone: 01483 68 2430

Find me on campus
Room: 06 AB 02


Journal articles

  • Birch DM, Shaw-Ward S, Titchmarsh A. (2014) 'Calibration and use of n-hole velocity probes.'. AIAA Journal: devoted to aerospace research and development, 53 (2), pp. 336-346.


    A generalized calibration process is presented for multi-hole, pressure-based velocity probes which is independent of the number of holes and probe geometry, allowing the use of probes with large numbers of holes. The calibration algorithm is demonstrated at low speeds with a conventional seven-hole pressure probe and a novel nineteen-hole pressure probe. Because the calibration algorithm is independent of probe configuration, it is very tolerant of data corruption and imperfections in the probe tip geometry. The advantages of using probes with large numbers of holes is demonstrated in a conventional wing wake survey. The nineteen-hole probe offers a higher angular sensitivity than a conventional seven-hole probe, and can accurately measure velocity components even when an analytical calibration scheme is used. The probe can also provide local estimates of the diagonal components of the cross-flow velocity gradient tensor in highly vortical flows.

  • Jammy SP, Hills N, Birch DM. (2014) 'Boundary conditions and vortex wandering'. Journal of Fluid Mechanics, 747, pp. 350-368.


    A direct numerical simulation of a Batchelor vortex has been carried out in the presence of freely-decaying turbulence, using both periodic and symmetric boundary conditions; the latter most closely approximates typical experimental conditions, while the former is often used in computational simulations for the purposes of numerical convenience. The higher-order velocity statistics were shown to be strongly dependent upon the boundary conditions, but the dependence could be mostly eliminated by correcting for the random, Gaussian modulation of the vortex trajectory commonly referred to as 'wandering' using a technique often employed in the analysis of experimental data. Once corrected for this wandering, the strong peaks in the Reynolds stresses normally observed at the vortex centre were replaced by smaller local extrema located within the core region but away from the centre. The distributions of the corrected Reynolds stresses suggested that the formation and organization of secondary structures within the core is the main mechanism in turbulent production during the linear growth phase of vortex development.

  • Birch DM, Rienties B. (2013) 'Effectiveness of UK and international A-level assessment in predicting performance in engineering'. Taylor and Francis Innovations in Education and Teaching International,
  • Birch DM, Martin N. (2013) 'Tracer particle momentum effects in vortex flows'. Cambridge Journals Journal of Fluid Mechanics, 723, pp. 665-691.


    The measurement of vortex flows with particle-image velocimetry (PIV) is particularly susceptible to error arising from the finite mass of the tracer particles, owing to the high velocities and accelerations typically experienced. A classical model of Stokes-flow particle transport is adopted, and an approximate solution for the case of particle transport within an axisymmetric, quasi-two-dimensional Batchelor q-vortex is presented. A generalized expression for the maximum particle tracking error is proposed for each of the velocity components, and the importance of finite particle size distributions is discussed. The results indicate that the tangential velocity component is significantly less sensitive to tracking error than the radial component, and that the conventional particle selection criterion (based on the particle Stokes number) may result in either over- or under-sized particles for a specified allowable error bound. Results were demonstrated by means of PIV measurements carried out in air and water using particles with very different properties.

  • Birch DM, Morrison JF. (2012) 'An innovative low-profile monolithic constant-temperature anemometer'. Elsevier Journal of Wind Engineering and Industrial Aerodynamics, 100 (1), pp. 38-45.


    A constant-temperature anemometer has been developed which uses a single high-fidelity speaker driver as a combined signal and power amplifier. Owing to its small size and simplicity of construction, the anemometer is well suited for applications requiring a large number of channels (such as hot-wire rakes) as well as applications requiring the embedding of instrumentation within confined experimental models (such as reduced-scale wind turbine blades). The anemometer is shown to have performance characteristics similar to those of a commercial anemometer when used under its design conditions. An operating bandwidth as high as 10 kHz can be achieved, which is greater than most available time-resolved digital particle-image velocimetry systems and is shown to be sufficient to track large-scale turbulence structures in channel flow.

  • Birch DM. (2012) 'Self-similarity of trailing vortices'. American Institute of Physics Physics of Fluids, 24 (2) Article number 025105


    Trailing vortices have been repeatedly shown to exhibit a remarkably robust self-similarity independent of the Reynolds number and upstream boundary conditions. The collapse of the inner-scaled circulation profiles of a trailing vortex has even been previously demonstrated for the cases of highly unsteady and turbulent vortex systems, as well as for vortices which were incompletely developed. A number of factors which contribute to and may artificially promote this self-similarity are discussed. It is shown that the amplitude of vortex “wandering” (or the random modulations in the vortex trajectory) observed in some experimental measurements are of sufficient amplitude to cause any arbitrary finite and axisymmetric flow structure to collapse with an idealized trailing vortex when scaled on inner parameters. It is further shown that, for the case of an incompletely developed wing-tip vortex, similarity in the outer core region may be an artefact of the rate of roll-up of the vortex sheet. Great care must, therefore, be taken when interpreting experimental measurements of vortex flows.

  • Birch DM, Morrison JF. (2011) 'Similarity of the streamwise velocity component in very-rough-wall channel flow'. CAMBRIDGE UNIV PRESS JOURNAL OF FLUID MECHANICS, 668, pp. 174-201.


    The streamwise velocity component is studied in fully-developed turbulent channel flow for two very rough surfaces and a smooth surface at comparable Reynolds numbers. One rough surface comprises sparse and isotropic grit with a highly non-Gaussian distribution. The other is a uniform mesh consisting of twisted rectangular elements which form a diamond pattern. The mean roughness heights (+/- the standard deviation) are, respectively, about 76 (+/- 42) and 145 (+/- 150) wall units. The flow is shown to be two-dimensional and fully developed up to the fourth-order moment of velocity. The mean velocity profile over the grit surface exhibits self-similarity (in the form of a logarithmic law) within the limited range of 0.04 < y/h < 0.06, but the profile over the mesh surface does not, even though the mean velocity deficit and higher moments (up to the fourth order) all exhibit outer scaling over both surfaces. The distinction between self-similarity and outer similarity is clarified and the importance of the former is explained. The wake strength is shown to increase slightly over the grit surface but decrease over the mesh surface. The latter result is contrary to recent measurements in rough-wall boundary layers. Single- and two-point velocity correlations reveal the presence of large-scale streamwise structure with circulation in the plane orthogonal to the mean velocity. Spanwise correlation length scales are significantly larger than corresponding ones for both internal and external smooth-wall flows.

  • Birch DM, Morrison JF. (2010) 'Large roughness effects in channel flow'. IUTAM Bookseries, 22, pp. 167-173.
  • Birch D, Lee T. (2005) 'Investigation of the near-field tip vortex behind an oscillating wing'. CAMBRIDGE UNIV PRESS JOURNAL OF FLUID MECHANICS, 544, pp. 201-241.
  • Birch D, Lee T. (2005) 'Tip vortex behind a wing undergoing deep-stall oscillation'. AMER INST AERONAUT ASTRONAUT AIAA JOURNAL, 43 (10), pp. 2081-2092.
  • Birch D, Lee T. (2005) 'Tip vortex behind a wing oscillated with small amplitude'. AMER INST AERONAUT ASTRONAUT JOURNAL OF AIRCRAFT, 42 (5), pp. 1200-1208.
  • Birch D, Lee T. (2005) 'Effect of trailing-edge flap on a tip vortex'. AMER INST AERONAUT ASTRONAUT JOURNAL OF AIRCRAFT, 42 (2), pp. 442-447.
  • Lee T, Birch D, Gerontakos P. (2004) 'Testing unmanned aerial vehicle airfoils'. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC IEEE INSTRUMENTATION & MEASUREMENT MAGAZINE, 7 (3), pp. 32-37.
  • Birch D, Lee T, Mokhtarian F, Kafyeke F. (2004) 'Structure and induced drag of a tip vortex'. AMER INST AERONAUT ASTRONAUT JOURNAL OF AIRCRAFT, 41 (5), pp. 1138-1145.
  • Lee T, Birch D, Gerontakos P. (2004) 'Vortex shedding and spacing of a rotationally oscillating cylinder'. AMER INST AERONAUT ASTRONAUT AIAA JOURNAL, 42 (6), pp. 1268-1272.
  • Birch D, Lee T, Mokhtarian F, Kafyeke F. (2003) 'Rollup and near-field behavior of a tip vortex'. AMER INST AERONAUT ASTRONAUT JOURNAL OF AIRCRAFT, 40 (3), pp. 603-607.

Conference papers

  • McParlin S, Ward S, Birch DM. (2013) 'Optimal calibration of directional velocity probes'. Grapevine, TX: 51st AIAA Aerospace Sciences Meeting


    A novel approach has been considered for the formal process of calibrating multiple hole pressure probes for use in wind tunnels. Rather than determining the attitude angles of a probe and subsequently flow angularity for a fixed probe, either by linear interpolation between sample points or through the use of piecewise functional fits, the outputs from the probe are mapped as continuous functions across the angular test space, using a set of sample points derived from Optimal Design of Experiments. This offers the potential of more accurate probe calibrations across a wider range of flow onset angles, with fewer sample points than currently used for the same purpose. Proof-of-concept tests using a five-hole probe have indicated that the approach is viable, while examination of fits to legacy data from prior tests indicates that the approach is easily extendable to probes with an arbitrary number of holes, and to multiple hot-wire installations.

  • Birch DM, Morrison JF. (2011) 'Similarity and Structure in Very-Rough-Wall Channel Flow'. Orlando, FL, USA: 49th AIAA Aerospace Sciences Meeting
  • Birch DM, Morrison JF. (2011) 'Scaling of Turbulence Structures in Very-Rough-Wall Channel Flow'. SPRINGER PROGRESS IN WALL TURBULENCE: UNDERSTANDING AND MODELING, Lille, FRANCE: WALLTURB International Workshop on Understanding and Modelling of Wall Turbulence 14, pp. 405-412.
  • Birch DM, Morrison JF. (2010) 'Velocity statistics of rough-wall channel flow'. Pennsylvania, USA: 16th US National Congress of Theoretical and Applied Mechanics
  • Birch DM, Morrison JF. (2010) 'Large Roughness Effects in Channel Flow'. SPRINGER IUTAM SYMPOSIUM ON THE PHYSICS OF WALL-BOUNDED TURBULENT FLOWS ON ROUGH WALLS, Clare Coll, Cambridge, ENGLAND: IUTAM Symposium on the Physics of Wall-Bounded Flows on Rough Walls 22, pp. 167-173.
  • Birch DM, Morrison JF. (2009) 'Effects of very-large roughness in turbulent channel flow'. SPRINGER-VERLAG BERLIN ADVANCES IN TURBULENCE XII - PROCEEDINGS OF THE 12TH EUROMECH EUROPEAN TURBULENCE CONFERENCE, Marburg, GERMANY: 12th EUROMECH European Turbulence Conference 132, pp. 661-664.
  • Birch DM, Morrison JF. (2008) 'Velocity scaling in very-rough-wall channel flows'. San Antonio, Texas, USA: 61st Annual Meeting of the American Physical Society Division for Fluid Dynamics
  • Birch DM, Morrison JF. (2007) 'Applicability of Townsend's similarity hypothesis to very rough-wall channel flow'. Salt Lake City, Utah, USA: 60th Annual Meeting of the American Physical Society Division for Fluid Dynamics 52 (12)
  • Birch D, Lee T. (2001) 'Control of unsteady shear layers over a cavity'. CANADIAN AERONAUTICS AND SPACE INST 48TH ANNUAL CONFERENCE OF THE CANADIAN AERONAUTICS AND SPACE INSTITUTE, PROCEEDINGS, TORONTO, CANADA: 48th Annual Conference of the Canadian-Aeronautics-and-Space-Institute, pp. 313-321.


  • Birch DM. (2009) Vector Dynamics: an Introduction for Engineering Students. Univeristy of Surrey
  • Morrison JF, Birch DM, Lavoie P. (2008) IUTAM Symposium on Flow Control and MEMS. Springer Verlag


  • Rampersad P, Nathan P, Birch D. A flow meter. Article number 1500257.9

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