Comment on ‘Effects of thermal radiation and slip mechanism on mixed convection flow of Williamson nanofluid over an inclined stretching cylinder’ (Commun.Theor.Phys.71 1405–15)
2022-08-02 03:01:20AsteriosPantokratoras
Asterios Pantokratoras
School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece
Abstract Some errors exist in the above paper.
The momentum equation (2) in [1] is as follows
First error
The units of concentration C are kg m?3(Nomenclature)whereas the pure number 1 is dimensionless.In Physics it is not allowed to add quantities with different units and the term(1 -C∞)is wrong.
Second error
In the term(T-T∞)λappears the parameterλwhich is dimensionless.However equation (1) is dimensional and this is irrational.
Third error
From figure 1 in[1]it is seen that gravity is present.However there is no gravity term in equation (1).
Fourth error
The mixed convection parameter is defined as follows in [1]
The units of concentration C are kg m?3(Nomenclature)whereas the pure number 1 is dimensionless.Therefore the term(1 -C∞)is wrong and the equation (2) is wrong.
Fifth error
For the same reason the buoyancy ratio parameter in [1]is wrong.In addition the appearance of dimensionless heat generation parameterβin equation (3) is irrational.
Sixth error
The dimensionless Brownian parameter is defined as follows in [1]
Seventh error
In the energy equation (3) in [1] appears the term
Eighth error
Equation (5) in [1] and the above figure 1 in [1] appears the equation
Communications in Theoretical Physics2022年7期
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