ISSN 0021-8944, Journal of Applied Mechanics and Technical Physics, 2018, Vol. 59, No. 1, pp. 186–187.
Pleiades Publishing, Ltd., 2018.
Original Russian Text
Orv¨os,V.Szab´o, and T. Po´os.
COMMENTS TO: “RATE OF EVAPORATION
FROM THE FREE SURFACE AT HEATED LIQUID”
[Journal of Applied Mechanics and Technical Physics
57 (6), 1108–1117 (2016)]
Orv¨os, V. Szab´o, and T. Po´os
This corrigendum serves the purpose of resolving any misunderstandings and shortcomings regarding the
The term “free water surface” used in the paper may be a subject of misunderstanding. The authors believe
that the ratio of evaporation rates and the gas ﬂow in the case of a “free water surface” is large enough that the
state of the gas hardly changes during evaporation. This means that the gas ﬂow parameters used to describe the
air entering and leaving the pool are nearly constant (relative humidity of air, absolute humidity of air, temperature,
and air velocity: ϕ
Sartori disagrees and says that this is a very particular deﬁnition of a free water surface, which is not found
elsewhere. He considers that the concept of the ‘free water surface’ is not related to the magnitudes of ﬂow rates,
but to the fact that the water surface is exposed to the external free environment without constraints such as a
cover, tube walls, or artiﬁcial human interferences on the ﬂows. He says that lakes, rivers, seas, pools, pans, etc,
are examples of free water surfaces, while a solar still is not because its cover conﬁnes and does not allow the air
ﬂow, evaporation, humidity, and water heating inside to be free. Moreover, Sartori says that, since the parameters
of our tests are constant and the water is heated electrically, this means that there are human interferences on the
air ﬂows and on evaporation rates; thus, the conditions are not free. The Sartori theoretical equations developed
for external free water surfaces in forced convection are not valid for internal ﬂows with artiﬁcial constraints and
free convection. According to Sartori, the updated Sartori equation  for a fully turbulent air ﬂow and forced
convection turned out to be the most accurate equation for free water surfaces among several well-known empirical
formulas and for free water surfaces of diﬀerent sizes and conditions.
Sartori remembers that the driving force for evaporation is the temperature diﬀerence and he demonstrated
all the categories, cases, or groups of evaporation and condensation (“negative” evaporation) based on temperature
diﬀerences. In his papers, Sartori demonstrated three categories, cases, or groups plus two categories, cases, or
groups on page 83 of his paper of 2000 . Sartori also highlights that the three cases involve the lower and upper
limits of temperatures for evaporation, that is, the evaporation occurs from T
up to T
, and thus the
evaporation takes place in between these limits, that is, at T
. Sartori  considered the evaporation that
happens at T
and 0 ϕ
100% and thus solved this issue correctly.
Where it reads “The problem of evaporation was described for the ﬁrst time in ” it should be read “Dalton
(1802) started the empirical hydrodynamic approach to the evaporation problem,” as cited in .
Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Hungary;
firstname.lastname@example.org. Corrected date January 15, 2018.
2018 by Pleiades Publishing, Ltd.