Skip to main content
Log in

Control of instabilities in non-Newtonian free surface fluid flows

  • Technical Paper
  • Published:
Journal of the Brazilian Society of Mechanical Sciences and Engineering Aims and scope Submit manuscript

Abstract

Free surface flows in inclined channels can develop periodic instabilities that are propagated downstream as shock waves with well-defined wavelengths and amplitudes. Such disturbances are called “roll waves” and are common in channels, torrential lava, landslides, and avalanches. The prediction and detection of such waves over certain types of structures and environments are useful for the prevention of natural risks. In this work, a mathematical model is established using a theoretical approach based on Cauchy’s equations with the Herschel–Bulkley rheological model inserted into the viscous part of the stress tensor. This arrangement can adequately represent the behavior of muddy fluids, such as water–clay mixture. Then, taking into account the shallow water and the Rankine–Hugoniot’s (shock wave) conditions, the equation of the roll wave and its properties, profile, and propagation velocity are determined. A linear stability analysis is performed with an emphasis on determining the condition that allows the generation of such instabilities, which depends on the minimum Froude number. A sensitivity analysis on the numerical parameters is performed, and numerical results including the influence of the Froude number, the index flow and dimensionless yield stress on the amplitude, the wavelength of roll waves and the propagation velocity of roll waves are shown. We show that our numerical results were in agreement with Coussot’s experimental results (1994).

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17

Similar content being viewed by others

Abbreviations

C * :

Dimensionless yield stress

Fr :

Froude number

Fr min :

Minimum Froude number

g :

Acceleration due to gravity

h :

Total depth of flow

h 0 :

Flow depth under uniform system

h 1 :

Flow depth before shock

h 2 :

Flow depth after shock

h c :

Critical flow depth

h z :

Domain of possible values for h 1

H :

Infinitesimal height value when the flow is disturbed

\( \hat{H} \) :

Magnitude of the disturbance

k :

Wavenumber of infinitesimal disturbances

K n :

Consistency rate of the Herschel–Bulkley fluid

l :

Characteristic width (channel width)

L :

Characteristic length

n :

Power-law index

P :

Pressure

P * :

Dimensionless pressure

t :

Time scale unit

u :

Velocity component in the x direction

u * :

Dimensionless velocity component in the x direction

\( \bar{u} \) :

Mean flow velocity

\( \bar{u}_{c} \) :

Mean flow velocity in h c

u 0 :

Velocity component in the flow direction under uniform system

\( \bar{u}_{0} \) :

Mean flow velocity under uniform system

U :

Vector velocity

U :

Roll wave propagation velocity

\( \hat{U} \) :

Infinitesimal value for the velocity flow when disturbed

w :

Velocity component in the z direction

w * :

Dimensionless velocity component in the z direction

x :

Abscissa in the Cartesian coordinate system

x * :

Dimensionless abscissa in the Cartesian coordinate system

x′:

Abscissa in the mobile system of coordinates

z :

Quota in the Cartesian coordinate system

z * :

Dimensionless quotas in the Cartesian coordinate system

z 0 :

Flow depth in the sheared region

α :

Velocity distribution coefficient

θ :

Slope of the channel

λ :

Length of roll wave

ρ :

Mass density

τ :

Shear stress

τ xz :

Shear stress acting on the x axis in the z direction

τ * :

Dimensionless shear stress

τ c :

Yield stress

τ b :

Wall stress

ω :

Frequency of infinitesimal disturbances

h :

Wave amplitude

References

  1. Cornish V (1934) Ocean waves and kindred geophysical phenomena. Cambridge University Press, Cambridge

    Google Scholar 

  2. Coussot P (1994) Steady, laminar, flow of concentrated mud suspensions in open channel. J Hydraul Res 32(4):535–559

    Google Scholar 

  3. Delahaye G, Coussot P (1996) Debris flows. Video, Cemagref-Min. Agr. (in French)

  4. Dressler RF (1949) Mathematical solution of the problem of roll waves in inclined open channels. Commun Pure Appl Math 2:149–194

    Article  MathSciNet  MATH  Google Scholar 

  5. Ferreira FO (2007) Abordagem matemática de roll waves em escoamentos hiperconcentrados com superfície livre. Master of Science Dissertation, Engineering College of Ilha Solteira, São Paulo State University, Ilha Solteira/SP 119p

    Google Scholar 

  6. Huang X, Garcia MH (1998) “A Herschel–Bulkley model for mud flow down a slope”, J Fluid Mech 374:305–333

    Article  MATH  Google Scholar 

  7. Ishihara T, Iwagaki Y, Iwasa Y (1954) Theory of the roll wave train in laminar water flow on a steep slope surface. Trans JSCE Japan 19:46–57

    Google Scholar 

  8. Jeffreys H (1925) The flow of water in an inclined channel of rectangular section. Philos Mag 49(6):793–807

    MATH  Google Scholar 

  9. Maciel GF, Vila JP, Martinet G (1997) Roll wave formation in the non-Newtonian flows. In: Proceedings of Congresso Brasileiro de Engenharia Mecânica, 14, Bauru. ABCM, p 98

  10. Maciel GF, Santos HK, Ferreira FO (2009) Rheological analysis of water clay compositions in order to investigate mudflows developing in canals. J Br Soc Mech Sci Eng ABCM 31(1):64–74

    Google Scholar 

  11. Ng CO, Mei CC (1994) Roll waves on a layer of fluid mud modeled as a power law fluid. J Fluid Mech 263:151–183

    Article  MATH  Google Scholar 

  12. Piau JM (1996) Flow of a yield stress fluid in a long domain, application to flow on an inclined plane. J Rheol N Y 40:711–723

    Article  MathSciNet  Google Scholar 

  13. Swaters GE (2003) Baroclinic characteristics of frictionally destabilized abyssal overflows. J Fluid Mech 489:349–379

    Article  MathSciNet  MATH  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Geraldo de Freitas Maciel.

Additional information

Technical Editor: Monica Naccache.

Rights and permissions

Reprints and permissions

About this article

Cite this article

de Freitas Maciel, G., de Oliveira Ferreira, F. & Fiorot, G.H. Control of instabilities in non-Newtonian free surface fluid flows. J Braz. Soc. Mech. Sci. Eng. 35, 217–229 (2013). https://doi.org/10.1007/s40430-013-0025-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40430-013-0025-y

Keywords

Navigation