Cristina and John, May 2010
Home in Vienna
Contact
EMail
JohnDFenton@gmail.com
Home address
StUlrichsPlatz 2/4
1070 Vienna
Austria
Phones:
Home +43 1 522 7467
Mobile/Handy/Cellulare:
John +43 664 7313 1035
Cristina +43 650 762 2417
Family History
John's mother spent many years researching the Family History


Collected papers
Recent publications
 Darvishi, E., Fenton, J. D. and Kouchakzadeh, S. (2017) Boussinesq equations for flows over steep slopes and structures, Journal of Hydraulic Research
55(3), 324337. Offprints available
A finiteslope Boussinesq equation is developed to model curved
transcritical flow over spillways and broadcrested weirs, even with
large slopes.
A number of laboratory experiments were performed
with
different transcritical flow problems including changes in channel
gradients and a trapezoidal weir. The equation and the numerical model
were
tested using results from those experiments and from those for a steep
and sharplycurved weir structure, with good results. They can be used
as a
computational flume to determine the headdischarge characteristics of
proposed structures. A novel feature of the equation and numerical
method is
that higher derivatives of the bed topography are best ignored,
apparently mimicking the effects of flow separation in smoothing it.
 Fenton, J. D. (2016) Hydraulics: science, knowledge, and culture, Journal of Hydraulic Research 54(5), 485501. Offprints available
The processes of thinking, research, dissemination, and use of research and knowledge in hydraulics are examined,
differentiating it from hydrology, and suggesting greater use of scientific methods and theories. At highly technical
levels, that is already done, but it is suggested that there is room for a greater simplicity of approach, based on
scientific rigour, recognising that much of what is done in hydraulics is modelling. This would make understanding,
access to, and participation in research easier for members of the profession. A number of recommendations and
conclusions are made. The article has a critical tone, but its main intention is to be helpful to individual hydraulicians
and to the profession at large. Suggestions are made as to how the profession might use the Web to give open access
to research findings and to create an open resource for hydraulics knowledge, as connection by colleagues in all
countries is now possible and feasible.
 Fenton, J. D. and Darvishi, E. (2016) Discussion of "Minimum specific
energy and transcritical flow in unsteady openchannel flow" by Oscar
CastroOrgaz and Hubert Chanson, Journal of Irrigation and Drainage Engineering 142(10), http://ascelibrary.org/doi/10.1061/(ASCE)IR.19434774.0001077
We show that there is no justification for the Singular Point Theory
of Massé (1938) for calculating transitional flows between sub and
supercritical flows.
 Fenton, J. D. (2015) Generating stream rating information from data,
Paper 8, Alternative Hydraulics.
The problem of using measurements of water level and discharge to generate stream rating curves is considered.
Current approaches are criticised. Two methods for the automatic processing of data and generation of curves are
developed, one based on global polynomials and the other on piecewisecontinuous approximating splines. Both are
found to work well. They allow the specification of a weight for each data point, enabling the filtering of data, possibly
incorporating its age, and allowing the computation of a rating curve for any time in the past up to the present. It
is suggested that ephemeral changes in bed resistance in some streams may play a more important role than usually
recognised, making results less certain. For such streams, with scattered or loopy data, the approximation methods
can be used to generate a rating envelope, allowing the calculation also of maximum and minimum expected flows.
 Fenton, J. D. (2015) Basic physical processes in rivers, Chapter 1 in
Rivers – Physical, Fluvial and Environmental Processes,
(eds) Paweł Rowiński and Artur RadeckiPawlik, Springer.
The governing long wave equations for a curved channel can be
developed with very few
limiting approximations, especially using momentum rather than energy.
The curvature is then shown to be rarely important and is subsequently
ignored. Wave periods,
imposed by boundary conditions, are asserted to be fundamental. Long
waves have
speeds and propagation properties that depend on period, and there is no
such thing
as a single long wave speed. Examination of dimensionless equations and
solution
of linearised equations using wave period shows a novel interpretation
of terms in
the momentum equation: the ”kinematic” approximation and wave are
misnomers:
the approximation lies not in the neglect of inertial terms but is
actually a very long
period one. The outstanding problem of river modelling, however, is that
of resistance to the flow. A large data set from streamgaugings is
considered and it is shown
that the state of the bed, namely the arrangement of bed grains by
previous flows, is
more important than actual grain size. A formula for resistance is
proposed which
contains a parameter representing bed state. As that state is usually
changing with
flow, one can not be sure what the resistance actually will be. This
uncertainty may
have important implications for modelling. The momentum principle is
then applied
also to obstacles such as bridge piers, and a simple approximation gives
greater understanding and a practical method for incorporation in river
models. Finally, river
junctions are considered, and the momentum approach with the very long
period
approximation shows that they can be modelled simpl


Lectures in hydraulics, numerics, and maritime
engineering
Introductory page
This is an introduction to
hydraulics. True energy conservation is presented, and
Bernoulli's equation is left to a subsidiary (and
occasionally useful) role. It is an integrated momentum
equation which is valid along a streamline and whose
"constant" varies across streamlines. It is absurd to
expect to apply it in fullyturbulent threedimensional
situations  for example the flow from a reservoir to a
tap in a house. It is much more intellectually honest
simply to use conservation of energy, which is more easily
derived and is a more plausible model of most hydraulic
problems.
A final year elective subject,
dealing with elementary oceanography, water wave theory,
tsunami, and coastal engineering
An introduction to waves and disturbances in channels,
measurement, and structures
An introduction to numerical methods, presenting theory
and applications largely using the optimisation package in
Microsoft Excel.
Coastal and Ocean Engineering  Steady water waves
A computer program ("Fourier") that solves the problem of
steadilyprogressing waves over a flat bottom is described
and made available here: Fourier
Programs that implement Stokes and cnoidal theories are
also available. The instructions file for all is Instructions.pdf.,
which is also included in Fourier.zip.
The latest changes are shown as highlighted comments.
The three wave programs are
 A Fourier approximation method whose only
approximation lies in truncating the number of terms in
the approximating series: Fourier.zip 
current version, 23 July 2015.
 An implementation of cnoidal theory, which is based on
series expansions in shallowness, requiring that the
waves be long relative to the water depth : Cnoidal.zip 
current version, 20 March 2015 (to be unpacked in a
subdirectory of the Fourier one). This is an
approximation, and not as applicable to higher waves as
the Fourier method. It can be used as a check on that
method  for long waves that are not high, both should
give the same results.
 An implementation of Stokes theory, requiring that the
waves be not too long relative to the water depth: Stokes.zip 
current version 20 March 2015 (to be unpacked in a
subdirectory of the Fourier one). This is also an
approximation, and not as applicable to higher waves as
the Fourier method. It can be used as a check on that
method  for waves that are not high or long, both
should give the same results.
